Stereoscopic image display device

Abstract

To provide a stereoscopic image display device capable of providing a sense of realism as if a displayed object actually exists at a displayed position.SOLUTION: A stereoscopic image display device includes a display device, a camera that detects the position of the user's viewpoint looking at this display device, and a rotation device that rotates the display device around a rotation axis passing through its display surface. This rotation device rotates the display device in synchronization with the movement of the user's viewpoint position so that the direction of the user's viewpoint as seen from the display surface does not change. A three-dimensional object defined in a world coordinate system that remains stationary relative to the real world is displayed on the display device, and when the user's viewpoint moves, an image of the object as seen from the direction of the user's viewpoint is displayed on the display device.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a stereoscopic image display device that effectively utilizes motion parallax. [Background technology]

[0002] A floating image display device is a device that displays two-dimensional images in the air, while a stereoscopic display device is a device that displays three-dimensional information. In terms of technical content, the two are independent concepts, but when an image is displayed as a mid-air image on a floating image display device, it appears to be floating above the surroundings, giving the viewer a sense of three-dimensionality. On the other hand, stereoscopically displayed images can sometimes give the same floating sensation as mid-air images.

[0003] Stereoscopic vision is a process that takes into account a variety of factors. One of the most important factors is binocular disparity. It has been revealed that neurons that respond to binocular disparity exist in multiple visual areas, and the relative distance between the gaze point and an object is calculated. This allows for the perception of depth.

[0004] Furthermore, even with two-dimensional images displayed on a regular display, factors such as perspective, occlusion of objects, shading, and texture can give the impression of front-to-back positioning and a sense of three-dimensionality. In other words, a virtual three-dimensional space constructed within a computer is displayed as a three-dimensional image by determining the viewpoint. Even though the display is two-dimensional, it is possible to create an image that appears three-dimensional by expressing the depth of objects and adding shadows and highlights. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2014-534656 [Patent Document 2] Japanese Patent Application Publication No. 2017-135543 [Patent Document 3] Japanese Patent Application Laid-Open No. 2008-146221 Summary of the Invention [Problem to be solved by the invention]

[0006] In addition to binocular parallax, techniques for achieving stereoscopic vision also use motion parallax. The visible range of objects and their relative positions change as the object moves or the viewing position shifts. This visual change is called motion parallax. This change can be used to obtain information about the front-to-back positional relationships between objects and depth information.

[0007] For example, when an object displayed on a two-dimensional display using 3D graphics is moved or rotated on the screen, a more three-dimensional effect is achieved, which is due to motion parallax.Technologies have also been proposed that obtain three-dimensional information from the motion parallax information contained in two-dimensional images (Patent Documents 1 and 2).

[0008] As a method of utilizing such motion parallax in video display, a technology has been proposed in which the movement of the user's viewpoint relative to the display is detected, and the image seen by the user is reproduced and displayed on the display, thereby creating a sense of stereoscopic vision (see, for example, Patent Document 3). However, with conventional displays that implement motion parallax, the display screen is viewed from an angle as the user's viewpoint moves, making it impossible to achieve a natural sense of three-dimensionality.

[0009] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a stereoscopic image display device that can provide a natural three-dimensional effect that makes it appear as if an object actually exists in space by more effectively utilizing motion parallax. [Means for solving the problem]

[0010] In order to solve the above problem, one aspect of the present invention provides a three-dimensional image display device comprising: a display device; a camera disposed in front of the display device and detecting the position of the viewpoint of a user facing the display device and viewing the display device; a rotation device on which the display device is mounted and which rotates the display device around a rotation axis; and an information processing device connected to the display device, the camera, and the rotation device, which receives the position of the user's viewpoint from the camera and changes the orientation of the display device by controlling the rotation of the rotation device in accordance with movement of the user's viewpoint position so that the orientation of the user's viewpoint as seen from the display surface does not change, wherein the information processing device displays three-dimensional objects defined in a world coordinate system that is immovable relative to the real world on the display device, and when the user's viewpoint moves, the information processing device displays an image of the object as seen from the direction of the user's viewpoint on the display device.

[0011] In one embodiment, the display device is a floating image display device capable of displaying a two-dimensional image in the air.

[0012] Furthermore, in one embodiment, the display device is an aerial image display device using a retro-transmission optical imaging element. [Effects of the Invention]

[0013] According to the stereoscopic image display device of the present invention, by more effectively utilizing motion parallax, it is possible to realize a stereoscopic view with a sense of realism never before seen. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective view showing a floating image display device 1 as a stereoscopic image display device according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, showing the aerial image display device 1 in use. [Figure 3]FIG. 3 is an explanatory diagram showing how the user's viewpoint moves relative to aerial image display device 1 in Example 1 of the present invention. [Figure 4] In Figure 4, (A1), (A2), and (A3) are plan views from above of the aerial image display device 1 according to the first embodiment of the present invention in use, (B1), (B2), and (B3) are figures for explaining how aerial images are displayed on the aerial image display device 1 corresponding to (A1), (A2), and (A3), and (C1), (C2), and (C3) are figures showing images displayed in the aerial image area G as aerial images on the aerial image display device 1. [Figure 5] FIG. 5 is a diagram for explaining perspective projection transformation performed in an aerial image display device 1 according to a second embodiment of the present invention. [Figure 6] Third Embodiment FIG. 6 is a perspective view showing a floating image display device 2 as a stereoscopic image display device according to a third embodiment of the present invention. [Figure 7] Fourth Embodiment FIG. 7 is a perspective view showing a floating image display device 3 as a three-dimensional image display device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of a stereoscopic image display device according to the present invention will be described with reference to the accompanying drawings. In the following embodiment, an aerial image display device equipped with a retro-transmission optical imaging element is used as an implementation example of the stereoscopic image display device. [Example]

[0016] [Structure of the aerial image display device] Fig. 1 is a perspective view showing a floating image display device 1 as a stereoscopic image display device according to Example 1 of the present invention. Fig. 2 is a cross-sectional view taken along line A-A in Fig. 1, showing the floating image display device 1 in use.

[0017] 1 and 2, the aerial image display device 1 includes, as essential components, a liquid crystal display 10 and an optical plate 20. The aerial image display device 1 also includes an information processing device 30 that controls the liquid crystal display 10, a speaker 40, and the like. The liquid crystal display 10, the speaker 40, and the information processing device 30 are housed inside the lower housing 12, and are each connected by signal lines (not shown).

[0018] The information processing device 30 is essentially a small computer and is composed of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), a storage device for storing various programs and data, an input / output interface, etc. Examples of input / output interfaces include a USB port and a wireless LAN such as Wi-Fi. The information processing device 30 outputs a video signal to the liquid crystal display 10, which displays the aerial image. The information processing device 30 also outputs an audio signal to the speaker 40, which generates voice guidance and sound effects. This information processing device 30 can also be a commercially available general-purpose small personal computer or a general-purpose tablet.

[0019] The liquid crystal display 10 is housed in a lower housing 12 that is rectangular in plan view and has an open top, and is supported almost horizontally with the display screen facing upward. The optical plate 20 is fitted into the upper housing 14 so that its incident surface 21 faces downward and faces diagonally to the display screen of the liquid crystal display 10. Here, the optical plate 20 and the liquid crystal display 10 are fixed at an angle of approximately 45 degrees.

[0020] An example of such an optical plate 20 is a retro-transmission optical imaging element (two-sided orthogonal reflector) described in Japanese Patent Laid-Open Publication No. 2011-175297. This optical imaging element is realized by arranging a large number of mutually orthogonal planar light reflecting portions at a fixed pitch. Alternatively, a two-sided corner reflector, in which reflective surfaces are formed on the side surfaces of a square hole, as described in Japanese Patent No. 4900618, may be used.

[0021] Furthermore, upper housing 14, which constitutes aerial image display device 1, can be easily separated from lower housing 12. Separating upper housing 14 makes it easier to perform maintenance and adjustments inside lower housing 12, and also reduces the height during transportation.

[0022] 2, light from the display screen of liquid crystal display 10 enters optical plate 20, reflects twice inside optical plate 20, and exits to the opposite side. As a result, aerial image G is formed as a real image in space on the opposite side of optical plate 20, with optical plate 20 as the target surface. In this case, to achieve a clearer aerial image G, it is desirable that external light not be added to the light from liquid crystal display 10.

[0023] Note that the aerial image G here illustrates the image area displayed in the air when an image is displayed across the entire display screen of the liquid crystal display 10. When a three-dimensional object is displayed in the center of the display screen of the liquid crystal display 10 and nothing is displayed in the other areas (when the other areas are displayed black), only the three-dimensional object is displayed in the air. Therefore, in the following description, the expression aerial image area G will also be used instead of aerial image G. Since the display screen of the liquid crystal display 10 is usually rectangular, the aerial image area G is also rectangular correspondingly. Note that in this specification, the aerial image area G will be referred to as the display surface of the aerial image display device 1.

[0024] Furthermore, a three-dimensional motion sensor 7 consisting of an infrared LED 72 and a pair of infrared cameras 74 is provided on the front side of the lower housing 12. This motion sensor 7 accurately detects the movement of the user's hand in three dimensions. The detection range of the motion sensor 7 is determined by the emission angle of the infrared LED 72 and the angle of view of the infrared camera 74. Such a motion sensor 7 can be a commercially available product such as Ultraleap's Leap Motion Controller 2.

[0025] In particular, this 3D motion sensor 7 is attached so that its tilt angle can be adjusted. That is, the motion sensor 7 is stored in a storage member that allows it to rotate within a certain angular range (here, ±20 degrees) around the rotation axis perpendicular to the paper surface of the cross-sectional view of Figure 2. Here, the center of the detection range of the motion sensor 7 is adjusted so that it is shifted toward the user from the center of the aerial image G. By adjusting it in this way, the effective operation detection range can be maximized.

[0026] Conventionally, such aerial image displays have often been used as administrative input devices for reception systems and the like. That is, by displaying a non-contact interface screen as the aerial image G, users can operate the non-contact interface screen using gestures such as touching it with their fingers. The operation is detected by a motion sensor 7 consisting of an infrared LED 72 and an infrared camera 74, and a corresponding operation signal is sent to the information processing device 30, where the specified processing is performed. The operation interface includes controls such as buttons, check boxes, and drop-down menus. Therefore, a completely non-contact interface can be realized with the same ease of use as a conventional touch panel.

[0027] Furthermore, aerial image display device 1 is placed on an electric rotating platform 50, and can freely rotate 360 ​​degrees around rotation axis R that passes vertically through the center of aerial image area G (the center of both the width and height of the area). That is, rotating platform 50 is made up of support base 52, rotating plate 56 pivoted on support base 52 by rotating shaft 54, rollers 57 that rotatably support rotating plate 56, and drive device 58 that rotates rotating plate 56. Therefore, rotating platform 50 serves as a rotation device that rotates aerial image display device 1 placed on it.

[0028] The driving device 58 is connected to and communicates with the information processing device 30 via a communication cable (not shown). The driving device 58 rotates the rotating plate 56 around the rotation shaft 54 ​​in response to a control signal from the information processing device 30, and calculates the rotation angle of the rotating plate 56 and transmits the calculated angle to the information processing device 30.

[0029] That is, drive device 58 is provided with a motor with an encoder, which rotates rotation plate 56 around rotation axis 54 and calculates the rotation angle of rotation plate 56. Then, servo control is performed to accurately control the rotation of aerial image display device 1.

[0030] Furthermore, a face detection camera 42 is provided above optical plate 20. This face detection camera 42 captures an image of the user's face from the front direction of aerial image display device 1 and detects the three-dimensional position of the user's eyes. A 3D camera equipped with a depth sensor can be used as this face detection camera 42. An example of such a 3D camera is Kinect (registered trademark).

[0031] Therefore, a face detection algorithm for detecting faces and identifying the positions of the eyes from images captured by face detection camera 42 is incorporated into information processing device 30. For example, yolo, which is capable of real-time processing, can be used as the face detection algorithm. This makes it possible to detect whether the user's viewpoint is shifted to the left or right from directly in front of aerial image display device 1.

[0032] Although not shown here, the aerial image display device 1 is placed on a table or the like at an appropriate height so that the aerial image can be viewed at eye level. In particular, a device equipped with an elevator that allows the height to be freely adjusted is suitable. An example of such an elevator is the Mario N electric elevator sold by Yamato Metal Works.

[0033] Coordinate System Here, we will define the coordinate systems used in this embodiment. The coordinate systems considered are the world coordinate system, the camera coordinate system, and the device coordinate system. These definitions are almost the same as the usage of general coordinate systems, but they have been slightly expanded and modified for the purpose of explanation.

[0034] First, we will explain the world coordinate system. Generally, the term world coordinate system refers to a coordinate system that defines the entire, immovable three-dimensional space on a computer, but in this specification, this definition is used in a more expanded manner. In other words, if the computer itself rotates, the three-dimensional space on the computer will rotate along with the computer. However, in this specification, we will consider a world coordinate system that is more absolutely stationary.

[0035] In other words, even if the computer (aerial image display device 1) itself rotates, the world coordinate system does not rotate and remains stationary relative to the external real world. Therefore, when the aerial image display device 1 rotates, other coordinate systems rotate relative to the external real world, but the world coordinate system does not move. Conversely, when viewed from the aerial image display device 1, the world coordinate system rotates relatively in the opposite direction by the amount of the detected rotation of rotation plate 56.

[0036] The world coordinate system is a right-handed system, and as shown in Figure 1, it is expressed as (x, y, z), with the up-down direction being the z-axis, the left-right direction being the y-axis, and the depth direction being the x-axis. The origin 0 is on the rotation axis 54 of the rotation plate 56. For the sake of explanation, the center of the aerial image area G (the center of both the width and height of this area) is taken as the origin O.

[0037] Next, the device coordinate system will be explained. The device coordinate system used here is a coordinate system on the display screen. Specifically, it is a coordinate system that indicates a position on the screen, with the aerial image area G being the display screen. It is expressed as three-dimensional coordinates (x', y', z') by adding the axis normal to the display screen. The device coordinate system (x', y', z') rotates with the rotation of the rotation plate 56, but at the specified position of the rotation plate 56, the device coordinate system (x', y', z') and the world coordinate system (x, y, z) coincide.

[0038] Next, the camera coordinate system will be described. Here, it is a three-dimensional coordinate system with the face detection camera 42 as the origin. In this embodiment, the camera coordinate values ​​of the center position of the user's left and right eyes detected by the face detection camera 42 (here, the center position of the line segment connecting the left and right eyes, called the viewpoint) are converted into values ​​in the coordinate system of the aerial image area G (device coordinate system (x', y', z')). This can be done by affine transformation.

[0039] This position of the user's viewpoint is used to calculate the horizontal angle δ of the user's viewpoint relative to the front of aerial image display device 1 (aerial image area G) (see Figure 3). This is calculated as δ = atan(y' / x'), where the viewpoint coordinates in the device coordinate system are (x', y', z'). This angle δ is sent to information processing device 30, which then uses servo control to rotate rotation plate 56 around rotation axis 54 so that angle δ becomes zero.

[0040] [How to implement 3D images] Below, a method for displaying a stereoscopic image using the aerial image display device 1 will be described with reference to the drawings. First, the target (object) for stereoscopic image display to be displayed in the aerial image area G is modeled in the world coordinate system. As described above, the aerial image display device 1 rotates, but the object is defined in the world coordinate system, and its position is determined relative to the real world (for example, the room in which the aerial image display device 1 is installed) regardless of the rotation of the aerial image display device 1. For simplicity, a cube is used as an example of the object, which is stationary in the world coordinate system. Needless to say, the present invention is not limited to cubes and can be applied to any three-dimensional object.

[0041] (A1), (A2), and (A3) in Figure 4 are plan views of the aerial image display device 1 as seen from above. In Figure 4 (A1), the user's viewpoint E is located in front of the aerial image display device 1 which is in the reference position. Here, as shown in Figure 2, the position where the back of the aerial image display device 1 faces the direction of the drive device 58 is set as the reference position of the aerial image display device 1.

[0042] If the user now moves slightly to the right and viewpoint E moves from the front of aerial image display device 1 to the right, face detection camera 42 detects this movement (angle δ) and transmits (notifies) it to information processing device 30. Information processing device 30 then controls drive device 58 to rotate aerial image display device 1 in accordance with the movement of user's viewpoint E so that the moved user's viewpoint E is positioned directly in front of aerial image display device 1.

[0043] That is, rotation plate 56 is rotated around rotation axis 54 so as to maintain the angle δ (= atan(y' / x')) between the direction directly in front of aerial image display device 1 and the direction of the user's viewpoint as seen from rotation axis R at 0. As a result, the rotation angle Φ of aerial image display device 1 relative to the reference position is always determined in synchronization with the movement of the user's viewpoint E, and the user always faces aerial image display device 1 directly in front (Figs. 4(A2) and (A3)).

[0044] (B1), (B2), and (B3) in Fig. 4 correspond to (A1), (A2), and (A3) in Fig. 4, and are diagrams for explaining how aerial images are displayed on the aerial image display device 1. In the figures, reference symbol C indicates a cube, but this is merely a convenient depiction of a cube as a target for stereoscopic image display and is not an actual displayed image. The images actually displayed as aerial images in the aerial image area G are (C1), (C2), and (C3) in Fig. 4.

[0045] The dashed line indicated by reference symbol G is the area of ​​the aerial image onto which the display screen of the liquid crystal display 10 is projected. Figures 4(C1), (C2), and (C3) are projections of a cube C, which is stationary in the world coordinate system as seen from the user's viewpoint E, onto the aerial image area G.

[0046] In Figure 4(B1), the aerial image display device 1 is at a reference position, and the aerial image area at that time is indicated by reference symbol Go. Furthermore, the user's viewpoint E is on the normal line to the aerial image area Go at the reference position. In this case, as shown in Figure 4(C1), only the front of the cube C is displayed.

[0047] Here, as shown in Fig. 4(B2), when user viewpoint E moves to the right, aerial image display device 1 rotates and follows so that aerial image area G faces user viewpoint E. The rotation angle Φ relative to aerial image area Go at the reference position at this time is shown. In this case, as shown in the projection view of Fig. 4(C2), a small portion of the right face of cube C is displayed.

[0048] As shown in Figure 4(B3), when user viewpoint E moves further to the right, aerial image display device 1 also rotates in synchronization. For example, when the rotation angle Φ becomes 45 degrees, as shown in Figure 4(C3), the projection of cube C is displayed so that the front and right side are equally visible.

[0049] Needless to say, the floating image area G is not visible to the user; only the displayed object (here, a cube) appears to be floating in the air. If the user wishes to see the displayed object from the side, they can simply shift their viewpoint to the side, revealing a previously unseen side. This allows the user to experience the same sensation as if the displayed object were actually there.

[0050] Therefore, the parallax caused by the movement of the observer's viewpoint, that is, the motion parallax, is implemented, which creates a motion depth effect and allows the user to perceive the displayed object in three dimensions. [Example]

[0051] In the first embodiment, the aerial image display device 1 rotates to follow the viewpoint E of the moving user, so that the user's viewpoint E is always positioned directly in front of it. However, because the aerial image display device 1 rotates mechanically, it is difficult to perfectly synchronize the user's viewpoint E with the front of the aerial image display device 1. That is, depending on the capabilities of the drive device 58, angle δ in Figure 3, which should ideally be close to 0, may become a concern.

[0052] Furthermore, if motion parallax is implemented for the vertical movement of the user's viewpoint E, a more realistic sense of presence can be achieved. To implement this mechanically, it would be necessary to implement rotation of the aerial image display device 1 around the y' axis in the above coordinate system, but this would be costly and would make the entire device large.

[0053] Therefore, in Example 2, the angle δ in Figure 3, i.e., the deviation between the user's viewpoint E and the front of the aerial image display device 1, is corrected using software. The specific method for this is explained below. For the sake of simplicity, we will consider only the movement of the user's viewpoint E in the horizontal direction.

[0054] In the explanatory diagram of Figure 5, when the user's viewpoint E shifts sideways by an angle θ relative to a cube C that is stationary in the world coordinate system, the aerial image display device 1 rotates to follow it. In reality, the angle of aerial image area G relative to aerial image area Go at the reference position should be θ (reference symbol Gt), but due to mechanical rotation delay, it becomes a smaller angle Φ. In other words, it shifts by an angle δ (= θ - Φ).

[0055] If the cube C were to be drawn in the floating image area G as it is, with the user's viewpoint E at angle θ, the floating image area G would be viewed from an angle, distorting the displayed image and ruining the sense of depth. Therefore, a conversion is performed so that the correct perspective view is obtained only when viewed from an angle. This is intended to create an optical illusion effect similar to that of road markings known as image humps. A detailed explanation is provided below.

[0056] When the user's viewpoint E is in front of the aerial image area G, the coordinates (device coordinates) of the projection surface (aerial image area G) are (y', z'), and the user's viewpoint E is located on the normal direction x'. However, due to a delay in the rotation of the aerial image display device 1, the user's viewpoint E is not on the normal direction x' of the projection surface (aerial image area G).

[0057] Therefore, using device coordinates, perspective projection transformation is performed from the user's viewpoint E to the diagonal aerial image area G of the cube C. In device coordinates, the coordinates of the user's viewpoint E are expressed as (e x ,e y ,e z ), and the coordinates of cube C are (c x ,c y ,c z ) The point where the line connecting these two points intersects with the projection plane (y'z' plane) is (p x ,p y ,p z ), then p y , p z is obtained (p x is always 0).

[0058] p y = (c y*e x -c x *e y ) / (e x -c x ) p z = (c z *e x -c x *e z ) / (e x -c x )

[0059] Figure 5 shows how the edges c1, c2, and c3 of cube C are projected onto points p1, p2, and p3 on the projection surface. Since the projection surface is the aerial image area G, it can be output as is as the display image on the LCD display 10. Since the displayed objects are typically opaque, hidden lines and surfaces are removed by hidden surface processing. Needless to say, the coordinate system of the display device often has its origin at the upper left corner, and measurement units must also be adjusted, so the output image will be converted appropriately.

[0060] By correcting the mechanical rotation delay with software in this way, the object appears smoothly to the user's eyes, allowing them to recognize the object's shape in a more natural, three-dimensional way. In the above explanation, the software correction (the above perspective projection transformation formula) is not limited to the horizontal direction; the parallax that occurs when the observer's viewpoint moves in the vertical and depth directions, i.e., motion parallax in the vertical and depth directions, is also implemented using the illusion effect. Of course, this is implemented within the range of viewing angles in the vertical and depth directions. This makes it possible to experience motion depth more effectively. [Example]

[0061] In Example 2, motion parallax is implemented by combining software correction with mechanical rotation of the aerial image display device 1, but it is also possible to implement motion parallax using software correction alone. However, when using retro-transmissive or retro-reflective types, the viewing angle is narrow, and the range in which the 3D image can be viewed is limited using software correction alone.

[0062] Therefore, in this third embodiment, motion parallax is implemented using only software correction in an aerial image display device with an expanded viewing angle.

[0063] FIG. 6 is a perspective view showing a floating image display device 2 as a third embodiment of a three-dimensional image display device. This floating image display device 2 includes a housing 60 having an M-shaped cross section, a pair of left and right liquid crystal displays 70a, 70b installed parallel to each other on the inside of both left and right sides of the housing 60, a pair of left and right optical plates 75a, 75b installed at a 45-degree angle relative to the pair of left and right liquid crystal displays 70a, 70b, a motion sensor 90 for detecting operations installed on the outside of the optical plates 75a, 75b, a face detection camera 82 installed on the top of the housing 60, a speaker 89, and a control device (not shown) that processes input and output signals from each of these elements. Again, the motion sensor 90 includes an infrared LED and an infrared camera. The functions of the motion sensor 90 and the face detection camera 82 are the same as those of the motion sensor 7 and the face detection camera 42 of the first embodiment, and therefore will not be described again.

[0064] It is assumed that the user will be standing when viewing this aerial image display device 2. As the vertical viewing angle of the aerial image display device 2 is not expanded, it is best viewed from the side, and the housing 60 is supported by legs 62 so that the aerial image is positioned at about eye height.

[0065] Here, the optical plates 75a and 75b are each the same rectangular shape and are arranged with one side of each plate in contact at a fixed angle (here, 90 degrees). However, the pair of liquid crystal displays 70a and 70b and the pair of optical plates 75a and 75b stand upright on the left and right, respectively. Overall, the liquid crystal displays 70a and 70b and the optical plates 75a and 75b are arranged symmetrically with respect to a plane that passes through the joining sides of the optical plates 75a and 75b and bisects the angle between the optical plates 75a and 75b.

[0066] Therefore, the image on the display screen of liquid crystal display 70a is formed as a real image at a position symmetrical with respect to the optical plate 75a, and the image on the display screen of liquid crystal display 70b is formed as a real image at a position symmetrical with respect to the optical plate 75b. These two real images partially overlap on the same plane and are formed as a single aerial image area Gx. However, the display of liquid crystal displays 70a and 70b is controlled so that the overlapping portion of the two real images (the central portion of the single aerial image area Gx) appears as the same image. This expands the aerial image area Gx compared to conventional aerial image display devices, resulting in a significantly larger viewing angle.

[0067] An object is displayed in this floating image area Gx in the same way as in Example 2. When the user's viewpoint moves, the above-mentioned perspective projection transformation is performed on the object and it is displayed in the floating image area Gx. This implements an optical illusion effect that allows the object to be correctly perceived as three-dimensional even when viewed from an oblique angle.

[0068] Therefore, it becomes possible to effectively experience motion depth over a wide horizontal viewing angle without physically rotating aerial image display device 2. As with Example 2, motion parallax is also implemented over a range of viewing angles in the vertical direction. [Example]

[0069] In the third embodiment, motion parallax is implemented in the up / down and left / right directions by combining vertical viewing angle expansion with mechanical rotation. Fig. 7 is a perspective view showing a floating image display device 3 that constitutes a stereoscopic image display device according to a fourth embodiment of the present invention.

[0070] 7, the aerial image display device 3 comprises a chair-shaped housing 13, a pair of LCD displays 20a, 20b installed inside the housing at an angle of approximately 45 degrees to the horizontal, a pair of optical plates 25a, 25b placed horizontally and vertically on the seat and back of the chair-shaped housing 13, a motion sensor 31 for detecting operations installed in front of the above, a speaker 39, and a control device (not shown) that processes input and output signals from each of these elements. The motion sensor 31 consists of a pair of infrared LEDs 32 and a pair of infrared cameras 34.

[0071] The pair of liquid crystal displays 20a, 20b and the pair of optical plates 25a, 25b are arranged in a 90-degree symmetrical manner with the relative positional relationship between liquid crystal displays 70a, 70b and optical plates 75a, 75b of the aerial image display device 2 shown in Figure 6 remaining unchanged. That is, optical plates 25a, 25b each have the same rectangular shape and are arranged with one edge of each plate in contact at a fixed angle (90 degrees in this case). Furthermore, liquid crystal displays 20a, 20b are arranged opposite optical plates 25a, 25b at a specified angle (45 degrees in this case). Overall, liquid crystal displays 20a, 20b and optical plates 25a, 25b are arranged symmetrically with respect to a plane that passes through the joint edges of optical plates 25a, 25b and bisects the angle between optical plates 25a, 25b.

[0072] Therefore, the image on the display screen of liquid crystal display 20a is formed as a real image at a position symmetrical with respect to the optical plate 25a, and the image on the display screen of liquid crystal display 20b is formed as a real image at a position symmetrical with respect to the optical plate 25b. Then, as with the aerial image display device 1 of Example 1, the images on the display screens of liquid crystal display 20a and 20b are formed as a single aerial image area G on the same plane. Aerial image area G is tilted by 45 degrees with respect to the vertical plane. Again, the overlapping portions of the two real images form the same image. This achieves an expansion of the viewing angle in the vertical direction only in the non-overlapping portions.

[0073] Similar to Example 1, the infrared LED 32 and infrared camera 34 of the motion sensor 31 photograph the user's hand near the aerial image area G to detect the position and movement of the user's hand. In addition, a face detection camera 42 is provided on the top of the housing 13, and similar to Example 1, photographs the user's face from the front of the aerial image display device 3 to detect the three-dimensional position of the user's eyes.

[0074] As in the first embodiment, the aerial image display device 3 is placed on an electrically driven rotating platform 50, and can freely rotate 360 ​​degrees around a rotation axis R that passes vertically through the center of the aerial image area G (the center of both the width and height of the area). The configuration of the rotating platform 50 is the same as that in the first embodiment.

[0075] The method of displaying a stereoscopic image by the aerial image display device 3 is the same as in Example 1, and therefore the details will not be repeated. That is, the information processing device controls the drive device of the turntable 50 to rotate the aerial image display device 3 in accordance with the movement of the user's viewpoint so that the user's viewpoint E is positioned directly in front of the aerial image display device 3.

[0076] This embodiment differs from Example 1 in that the viewing angle in the vertical direction is expanded. That is, horizontal motion parallax is handled by mechanical rotation of aerial image display device 3, and vertical motion parallax is handled by expanding the viewing angle.

[0077] In the first embodiment, the aerial image area G stands upright, but in the fourth embodiment, the aerial image area G is tilted at an angle of 45 degrees, so the image is as if viewed from diagonally above. [Industrial Applicability]

[0078] The stereoscopic image display device of the present invention realizes a stereoscopic view with a sense of realism never before seen, and for example, it is possible to exhibit cultural assets such as clay statues and earthenware using 3D data, making it appear as if the real thing were actually there.

[0079] Here, a cube is used as an example of an object to be displayed on the aerial image display device 1, and is described as being stationary in the world coordinate system. However, the present invention can be implemented even if the object undergoes any time-dependent changes (such as rotation or deformation) in the world coordinate system. For example, if the object is the Earth, the Earth rotating relative to the world coordinate system can be viewed from various angles.

[0080] Furthermore, in the above embodiment, an aerial image display device using a retro-transmissive optical imaging element is used, but the present invention is not limited to this, and for example, an aerial image display device using a retro-reflective optical imaging element may also be used.

[0081] Furthermore, the spirit of the present invention can be expected to have a certain degree of effectiveness even if it does not necessarily use aerial images, and therefore the present invention can also be implemented using general displays such as LCD displays and OLED displays. [Explanation of symbols]

[0082] 1, 2, 3 Aerial image display device 7. Motion Sensor 10 LCD display 12 Lower housing 13 Chair-shaped enclosure 14 Upper housing 20 Optical Plate 20a, 20b LCD display 21 Entrance plane 25a, 25b Optical plates 30 Information processing equipment 31 Motion Sensor 32 infrared LEDs 34 Infrared Camera 39, 40 speakers 42 Face detection camera 50 Rotating Platform 52 Support stand 54 Rotating shaft 56 Rotating Plate 57 Coro 58 Drive Unit 60 cabinets 62 Legs 70a, 70b LCD display 72 infrared LEDs 74 Infrared Camera 75a, 75b Optical Plates 82 Face detection camera 89 Speakers 90 Motion Sensor 90 degrees (here G, Go, Gx aerial image area

Claims

1. a display device; a camera provided in front of the display device to detect the position of a viewpoint of a user facing the display device and viewing the display device; a rotation device that rotates the display device around a rotation axis; an information processing device connected to the display device, the camera, and the rotation device, which receives a position of the user's viewpoint from the camera, and changes the orientation of the display device by controlling the rotation of the rotation device in response to a movement of the position of the user's viewpoint so that the orientation of the user's viewpoint as seen from the display surface does not change; the information processing device causes the display device to display a three-dimensional object defined in a world coordinate system that is immovable relative to the real world; When the user's viewpoint moves, the information processing device displays an image of the object as seen from the direction of the user's viewpoint on the display device.

2. 2. The stereoscopic image display device according to claim 1, wherein the display device is a floating image display device capable of displaying a two-dimensional image in the air.

3. 3. The stereoscopic image display device according to claim 2, wherein the display device is an aerial image display device using a retro-transmission optical imaging element.

Images