Three-dimensional video display device

Abstract

Provided is a three-dimensional video display device capable of providing a sense of presence as though a displayed object were actually present.　The three-dimensional video display device comprises: a display device; a camera that detects the position of a viewpoint of a user viewing the display device; and a rotation device that rotates the display device about a rotation axis passing through a display surface thereof. The rotation device rotates the display device in accordance with the movement of the position of the user's viewpoint so that the orientation of the user's viewpoint as viewed from the display surface does not change. Further, a three-dimensional object defined by a world coordinate system that is immobile with respect to the real world is displayed on the display device, and if the user's viewpoint moves, an image of the object when viewed from the direction of the user's viewpoint is displayed on the display device.

Description

Three-dimensional video display device

[0001] The present invention relates to a three-dimensional video display device that can be perceived stereoscopically with the naked eye.

[0002] A three-dimensional video display device is a device that makes a certain object be perceived as if it exists in the same space as the observer in a three-dimensional manner. Currently, as display methods for three-dimensional videos, there are roughly two major types: glasses-type and naked-eye type.

[0003] In the glasses-type, there is a type that presents different images to the right eye and the left eye by having the user wear special 3D glasses to obtain a stereoscopic effect. Such special 3D glasses include glasses with red and blue color filters on the left and right (anaglyph glasses), polarized glasses that utilize orthogonally linearly polarized light, and liquid crystal shutter glasses that view videos shot from different angles on the left and right in a time-division manner.

[0004] The naked-eye type is one in which an optical system for separating the images for the right eye and the left eye is arranged on the display surface of the display device. For example, there is the parallax barrier method that creates binocular disparity by setting up a shielding plate with one hole or groove for every two left and right pixels in front of the display pixels so that different pixels can be seen by the left and right eyes, and the lenticular lens method that uses a lenticular lens instead of the shielding plate.

[0005] Japanese Patent No. 7224017

[0006] The above glasses-type and naked-eye type three-dimensional video display devices present different images to the right eye and the left eye to obtain a stereoscopic effect, that is, they provide binocular disparity. In fact, most of the currently commonly used three-dimensional video display devices utilize such binocular disparity.

[0007] However, for three-dimensional video display devices based on binocular disparity, there are contradictions regarding other factors of stereoscopic vision such as focus adjustment, convergence, and motion parallax, and a sense of discomfort may be felt when looking at them for a long time. This is the so-called 3D sickness.

[0008] In response to this, several volumetric displays have been proposed. These displays project three-dimensional objects directly into space. However, due to the high demands on each component, the high costs involved, and performance limitations, many of these proposals remain in the research stage.

[0009] For example, the volumetric display described in Patent Document 1 achieves stereoscopic vision by stacking transparent displays. While this volumetric display can indeed display a true three-dimensional object in the center of the stacked glass plates, the stack of numerous glass plates is also visible, giving the impression that the object is embedded within it. Furthermore, the display device itself is not completely transparent, and the view appears cloudier the deeper you go into the multiple layers.

[0010] Therefore, the objective of the present invention is to provide a three-dimensional image display device that can display a three-dimensional object in empty space without any sense of incongruity.

[0011] To solve the above problems, a three-dimensional image display device according to one aspect of the present invention comprises a plurality of display devices arranged parallel to each other and transparent except for at least the one located furthest back; an optical system that projects the images displayed on each of the display devices into the air and displays the aerial images on a plurality of projection surfaces that are also arranged parallel to each other; and an information processing device that supplies an image signal to each of the display devices and displays an image on each of the display devices, wherein the information processing device sets a three-dimensional object to be displayed in the three-dimensional space between the projection surfaces and displays an image representing this three-dimensional object on each of the display devices.

[0012] In one embodiment, the system further includes a camera that detects the viewpoint position of a user facing the three-dimensional image display device and viewing the three-dimensional image display device. The information processing device receives the viewpoint position information of the user from the camera, and, in conjunction with the movement of the user's viewpoint position, performs perspective projection transformation of the three-dimensional object for each of the projection surfaces with this viewpoint position as the projection center, calculates the image to be displayed on each of the projection surfaces in real time, and supplies the calculated image signal to the display device.

[0013] Furthermore, in one embodiment, the display device, when performing perspective projection transformation on each point of the three-dimensional object, performs perspective projection transformation on both of the two projection surfaces flanking each point, and allocates the brightness of each point according to the distance between each point and the projection surface.

[0014] Furthermore, a three-dimensional image display device according to another aspect of the present invention comprises a transparent first display device and a second display device arranged parallel to each other; an optical system that projects the image displayed on the first display device into the air to display a first aerial image, and projects the image displayed on the second display device into the air through the first display device to display a second aerial image at a position parallel to and separated from the first aerial image; and an information processing device that supplies video signals to the first and second display devices and displays videos on the first and second display devices, respectively, wherein the information processing device sets a three-dimensional object to be displayed in the space between the aerial images and displays a video representing this three-dimensional object on the first and second display devices, respectively.

[0015] The three-dimensional image display device according to the present invention makes it possible to achieve stereoscopic viewing as if a three-dimensional object were actually present there.

[0016] Figure 1 is a perspective view showing an aerial image display device 1 as a three-dimensional image display device according to Embodiment 1 of the present invention. Figure 2 is a cross-sectional view of the aerial image display device 1 along the line A-A in Figure 1. Figure 3 is a diagram illustrating the perspective projection transformation performed in the aerial image display device 1. Figure 4 is a diagram illustrating the perspective projection transformation performed in the aerial image display device 1, and is a diagram illustrating the perspective projection transformation performed on the two projection planes in front of and behind the coordinates of the object to be displayed. Figure 5 is a perspective view showing an aerial image display device 2 as a three-dimensional image display device according to Embodiment 2 of the present invention. Figure 6 is a cross-sectional view of the aerial image display device 2 along the line A-A in Figure 1.

[0017] Hereinafter, embodiments of the three-dimensional image display device according to the present invention will be described with reference to the attached drawings. In the following embodiments, an aerial image display device equipped with a retrotransmissive optical imaging element is shown as an example of the implementation of the three-dimensional image display device.

[0018] [Structure of Aerial Image Display Device] Figure 1 is a perspective view showing an aerial image display device 1 as a three-dimensional image display device according to Embodiment 1 of the present invention. Figure 2 is a cross-sectional view of the aerial image display device 1 along the line A-A in Figure 1.

[0019] As shown in Figures 1 and 2, the aerial image display device 1 includes a three-dimensional display 10 and an optical plate 20 as essential components. The aerial image display device 1 also includes an information processing device 30 for controlling the three-dimensional display 10, and a speaker 40. Here, the three-dimensional display 10, speaker 40, and information processing device 30 are housed inside the lower housing 12 and are connected to each other by signal lines (not shown in the figures).

[0020] The information processing device 30 is essentially a small computer and consists of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), a storage device for storing various programs and data, and an input / output interface. The input / output interface may include, for example, a USB port or a wireless LAN such as Wi-Fi. The information processing device 30 outputs video signals to the three-dimensional display 10 to display the basis for the aerial image. The information processing device 30 also outputs audio signals to the speaker 40 to generate guidance voices and sound effects. This information processing device 30 can also utilize commercially available general-purpose small personal computers or general-purpose tablets.

[0021] The three-dimensional display 10 is housed in a lower enclosure 12 that is rectangular in shape when viewed from above and has an open top. It is constructed by stacking multiple (in this case, eight) transparent display panels 10-1, ... 10-8. Each transparent display panel is supported horizontally with its display screen facing upwards and is held at equal intervals from one another. For example, the transparent display panels 10-1, ... 10-8 are held at intervals of 1.5 cm, and the overall thickness of the three-dimensional display 10 is approximately 12 cm.

[0022] Each of the transparent display panels 10-1, ... 10-8 is a 12-inch transparent inorganic EL panel with a resolution of 640 x 480 pixels. This transparent inorganic EL panel has a first transparent electrode, a first insulating layer, an inorganic EL layer, a second insulating layer, and a second transparent electrode formed in that order on a transparent substrate, with another transparent substrate provided on top of that. A glass substrate can be used as the transparent substrate.

[0023] An inorganic electrochromic layer is a layer containing an inorganic electrochromic material that remains transparent when no voltage is applied and emits light when a voltage is applied. Examples of materials used for such an inorganic electrochromic layer include ZnS:Tb, which is ZnS doped with Tb, and ZnS:Mn, which is ZnS doped with Mn.

[0024] Furthermore, the first transparent electrode consists of numerous elongated electrodes extending parallel to one direction. The second transparent electrode has a similar configuration to the first transparent electrode, but its extension direction is perpendicular to that of the first transparent electrode, and together with the first transparent electrode, it forms a simple matrix type (passive type) drive circuit. Examples of materials for the first and second transparent electrodes include transparent conductive oxides such as ITO and IZO.

[0025] The first and second insulating layers separating the transparent electrode and the inorganic EL layer are transparent insulating films, and materials such as Al₂O₃, TiO₂, and SiO₂ can be used. Examples of such transparent inorganic EL panels include the product name TASEL (manufactured by Beneq). The transparency of each transparent display panel is 80% or higher.

[0026] The support 18 that holds these transparent display panels 10-1, ... 10-8 houses a control circuit that supplies scanning pulses and data pulses to each transparent display panel (first and second transparent electrodes). This control circuit receives image signals from the information processing device 30 via an HDMI® cable (not shown in the figure) and can display different images on each of the transparent display panels 10-1, ... 10-8.

[0027] Specifically, the information processing device 30 generates a single image containing eight 640 x 480 pixel images, and transmits this image to the control circuit in the support 18. The control circuit separates the received image into eight 640 x 480 pixel image signals and supplies them to each transparent display panel for independent control.

[0028] Furthermore, the optical plate 20 is fitted into the upper housing 14 with its incident surface 21 facing downwards, so as to be obliquely facing the display screen of the three-dimensional display 10. Here, the optical plate 20 and the three-dimensional display 10 are fixed at an angle of approximately 45 degrees.

[0029] As such an optical plate 20, for example, a retrotransmitting optical imaging element (two-plane orthogonal reflector) described in Japanese Patent Application Publication No. 2011-175297 can be used. This optical imaging element is realized by arranging a large number of mutually orthogonal planar light reflecting parts at a constant pitch. In addition, structures such as a two-plane corner reflector, in which reflective surfaces are formed on the sides of a square-shaped hole, as described in Japanese Patent No. 4900618, may also be used.

[0030] Furthermore, the upper housing 14 that constitutes the aerial image display device 1 can be easily separated from the lower housing 12. Separating the upper housing 14 makes it easier to perform maintenance and adjustments inside the lower housing 12, and also reduces the height during transportation.

[0031] As shown in Figure 2, light from each display screen of the transparent display panels 10-1, ... 10-8 enters the optical plate 20, is reflected twice inside the optical plate 20, and exits to the opposite side. As a result, an aerial image as a real image is formed in the space opposite to the optical plate 20, with the optical plate 20 as the plane of symmetry. The rectangular areas shown by dashed lines in Figures 1 and 2 represent projection surfaces G-1, ... G-8 corresponding to each display screen of the transparent display panels 10-1, ... 10-8. These projection surfaces G-1, ... G-8 are arranged in the front-to-back direction with y and z directions spaced 1.5 cm apart, with the front-to-back direction of the aerial image display device 1 being the x-direction, the left-to-right direction being the y-direction, and the up-to-down direction (vertical direction) being the z-direction.

[0032] Therefore, the aerial image can be displayed as a three-dimensional aerial image area G with a thickness of 12 cm, corresponding to the eight display screens of the three-dimensional display 10. If a three-dimensional object is displayed in the center of the aerial image area G of the three-dimensional display 10, and nothing is displayed in the other areas (i.e., they are black), only the three-dimensional object will be displayed floating in the air.

[0033] 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 precisely detects the user's hand movements in three dimensions. The detection range of the motion sensor 7 is defined by the emission angle of the infrared LED 72 and the field of view of the infrared cameras 74. Such a motion sensor 7 can be a commercially available product, such as the Leap Motion Controller 2 from Ultraleap.

[0034] In particular, the three-dimensional motion sensor 7 is mounted in a way that allows its tilt angle to be adjusted. That is, the motion sensor 7 is housed in a housing that allows it to rotate within a certain angular range (here, ±20 degrees) with the axis of rotation perpendicular to the plane of the cross-sectional view in Figure 2. Here, the center of the detection range of the motion sensor 7 is adjusted to be shifted towards the user side from the center of the aerial image region G. By making this adjustment, the effective operation detection range can be maximized.

[0035] Furthermore, a face detection camera 42 is provided above the optical plate 20. This face detection camera 42 captures the user's face from the front of the 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 such a face detection camera 42. Examples of such 3D cameras include Kinect®.

[0036] Therefore, a face detection algorithm is incorporated into the information processing device 30 to detect faces from images captured by the face detection camera 42 and to further determine the position of the eyes. For example, YOLO, which enables real-time processing, can be used as the face detection algorithm. This makes it possible to detect the movement of the user's gaze.

[0037] Although not shown in the diagram, the aerial image display device 1 is placed on a table or similar surface at an appropriate height so that the aerial image can be viewed at eye level. In particular, a device with a lifting mechanism that allows the height to be freely adjusted is suitable. An example of such a lifting mechanism is the electric lifting device Mario N sold by Yamato Metal Works.

[0038] Next, with reference to the diagram, we will explain the specific method of displaying stereoscopic images using the aerial image display device 1. First, the object to be displayed as a stereoscopic image in the air is modeled in a world coordinate system. In the world coordinate system, as shown in Figure 1, the front-to-back direction of the aerial image display device 1 is the x-direction, the left-to-right direction is the y-direction, and the up-to-down direction is the z-direction. The origin of the world coordinate system can be the center of the aerial image area. For example, the origin of the world coordinate system is the center of the projection surface G-4 of the transparent display panel 10-4. In this case, the x-coordinate of the projection surface of the transparent display panel 10-4 is 0. The x-coordinates of the projection surfaces of the other transparent display panels are integer multiples of d, where d is the distance between the projection surfaces.

[0039] The three-dimensional position of the user's eyes, detected by the face detection camera 42, is also converted to world coordinate system values ​​(x, y, z) and used. This can be done using an affine transformation. In this embodiment, the viewpoint is the center position of both the left and right eyes of the user detected by the face detection camera 42, that is, the midpoint of the line segment connecting the left and right eyes.

[0040] If a considerable number of transparent display panels were stacked even more densely, it might be possible to display each point of the 3D object being displayed on the nearest pixel, but this is difficult to implement. In other words, there are wires to each transparent display panel, and there is a limit to the possible stacking interval. Also, even if dense stacking were possible, the light from the lower panels would be greatly weakened because it would pass through many panels on top.

[0041] Therefore, in this embodiment, depth-fused 3D (DFD) illusion and perspective projection transformation are used to display effective stereoscopic images on a limited number of transparent display panels.

[0042] The DFD illusion is a phenomenon where two identical images are superimposed on two transparent surfaces, one in front and one behind, causing them to be perceived as a single, fused image at the depth position between the two surfaces. Here, the perceived depth position can be altered by changing the brightness of the two surfaces.

[0043] In the DFD illusion, the corresponding coordinate points on the front and back surfaces must overlap from the viewpoint. Therefore, real-time perspective projection transformation is performed to ensure that the corresponding coordinate points remain in line of sight even when viewed from a horizontally shifted position.

[0044] First, the perspective projection transformation will be explained. When a three-dimensional object is displayed on a two-dimensional display device, if the display screen is viewed obliquely, it will be distorted and the three-dimensional effect will be impaired. Therefore, a perspective projection transformation is performed so that a correct perspective view is obtained only when viewed obliquely. This is for the purpose of the same kind of illusion effect as, for example, what is called an image bump in road markings. This perspective projection transformation is performed in real time in synchronization with the change in the position of the user's eyes detected by the face detection camera 42. Thereby, motion parallax is implemented. Also, the misalignment between the front and rear two surfaces, which is a problem in the DFD illusion, is eliminated.

[0045] Specifically, in the world coordinate system, let the coordinates of the user's viewpoint E as the projection center be (e x , e y , e z ), and the coordinates of the object to be displayed be (c x , c y , c z ). If the projection point where the straight line connecting these two points intersects the projection plane is (p x , p y , p z ), then p y , p z are obtained as follows (see Figure 3).

[0046] 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 )

[0047] Here, p xSince is always set to 0, this formula finds the projection point of a projection plane on the origin of the world coordinate system (for example, the projection plane of the transparent display panel 10-4). For other projection planes, the world coordinate system is first translated in the x direction by an integer multiple of the distance d between projection planes to move the origin onto that projection plane, then the perspective projection transformation is performed using the above formula, and the result is translated in the reverse direction back to the original world coordinate system. Note that the above formula finds the coordinate point (c') on the opposite side of the projection plane. x , c' y , c' z Similarly, the projection point (p' x ,p' y ,p' z It can also be used to find ).

[0048] Furthermore, in order to implement the DFD illusion, when performing perspective projection transformations on each point of a three-dimensional object, perspective projection transformations are performed on both the two projection planes flanking each point, and the brightness of each point is allocated according to the distance between each point and each projection plane.

[0049] Specifically, if the coordinates of the object to be displayed are on the projection plane, it will be displayed as is without transformation. If the coordinates of the object to be displayed are in an area between adjacent projection planes, the perspective projection transformation described above will be performed. The perspective projection transformation will be performed on both the near and far sides of the object's coordinates.

[0050] That is, referring to Figure 4, the coordinates (c) of the object to be displayed. x ,c y ,c z ) is transformed into a perspective projection onto the far projection plane P (for convenience, let's call it the projection plane on the origin), and the projection point (0, p y , p z ) Similarly, the coordinates of the object to be displayed (c x ,c y ,c z ) is transformed into a perspective projection onto the projection plane P' on the near side, and the projection point (d, p' y ,p' z )

[0051] Thus, except when the coordinates of the object to be displayed are on the projection plane, projection points are obtained on two projection planes, one before and one after the coordinates. These two projection points are merged to implement the DFD illusion.

[0052] That is, the coordinates of the object (c x ,c y ,c z Let Y be the brightness at ) and the projection point (0, p y , p z Brightness y of ) and projection point (d, p' y ,p' z Set the brightness y' of ) as follows.

[0053] y = ((d - c x ) / d)Y y'=(c x / d) Y

[0054] These projection points overlap and merge into one from the user's perspective, and the depth direction is c x It is perceived as such. This is a depth-merging stereoscopic illusion. The above explanation concerns the projection plane on the origin, but for other projection planes, the brightness of the projection points can be calculated similarly, with only the depth direction shifting by an integer multiple of the interval d. In addition, for color displays, the values ​​for each RGB component are determined according to the formula above.

[0055] The above calculation formula does not take into account the transparency of the transparent display panel. In reality, uniform display can be achieved by adjusting the brightness of the upper transparent display panel to match the brightness of the lower transparent display panel.

[0056] Therefore, the brightness of the bottommost transparent display panel 10-1 is set to the maximum, and the brightness decreases by the transparency of each panel above it. If the brightness of the transparent display panel 10-n obtained by the above calculation formula is y, and the transparency is t, then the actual brightness is t(n-1)y. For example, if the transparency is 0.85, the brightness of the topmost transparent display panel 10-8 is approximately 32% (0.85) compared to the bottommost transparent display panel 10-1. 7 Reduce it to ).

[0057] The bottommost transparent display panel 10-1 may be replaced with a non-transparent, standard display panel. For example, a standard liquid crystal display panel or an organic EL panel can be used. Since these can have higher brightness than transparent display panels, the brightness of the second-to-last transparent display panel 10-2 is set to the maximum, and the brightness of the top panel is set to approximately 118% (1 / 0.85) higher than that. In that case, the brightness of the topmost transparent display panel 10-8 is approximately 38% (0.85) of the maximum brightness. 6 The decrease will be limited to that point.

[0058] Furthermore, the term "projection surface" was used in the above explanation, but "projection" here has two meanings. One is "projection" which means that the image from a transparent display panel is projected onto the projection surface by an optical plate. The other is "projection" which refers to the perspective projection transformation of a three-dimensional object, with the viewpoint as the projection center.

[0059] As the display image for each projection surface is determined as described above, it can be output directly as the display image for the three-dimensional display 10. Note that, since the displayed object is usually opaque, hidden lines and surfaces are removed by hidden surface processing.

[0060] In this way, a practical volumetric display can be realized, but as the number of layers increases, the effective brightness decreases. Therefore, when exhibiting the 3D image display device of Example 1, it is best to have people view it in a darkened room or space.

[0061] In Example 1, multiple transparent display panels are stacked, which inevitably reduces the effective brightness. Therefore, in the 3D image display device of Example 2, 3D images are realized using only two display panels, similar to the implementation of a typical DFD illusion.

[0062] Figure 5 is a perspective view showing an aerial image display device 2 as a three-dimensional image display device according to Embodiment 2 of the present invention. Figure 6 is a cross-sectional view along line A-A in the figure showing the aerial image display device 2 in use. In the figures, the same reference numerals are used for components that are the same as in Embodiment 1, and redundant explanations are not provided. The following describes the configurations that differ from Embodiment 1.

[0063] In the aerial image display device 2 of Embodiment 2, instead of the transparent display panels 10-1, ... 10-8 of Embodiment 1, a transparent display 11 and a normal non-transparent display 13 are provided. The transparent display 11 and the display 13 are arranged parallel to each other with a distance D between them.

[0064] The transparent display 11 may be a transparent inorganic EL panel, as in Example 1, but it may also be a transparent organic EL panel. Currently, transparent organic EL panels have lower transparency than transparent inorganic EL panels, often around 50%, but they have the advantage of being able to display higher quality colors than transparent inorganic EL panels. Also, the display 13 can be a regular, non-transparent organic EL panel, but it may also be a liquid crystal display with a backlight.

[0065] The information processing device 32 can be a standard personal computer, supports multiple displays, and is connected to displays 11 and 13 by display cables such as HDMI® cables (not shown in the diagram).

[0066] Here, as shown in Figure 5, the world coordinate system is defined as the x-direction for the front-to-back direction of the aerial image display device 2, the y-direction for the left-to-right direction, and the z-direction for the up-to-down direction. The origin of the world coordinate system is set to the center of the projection surface G1 of the transparent display 11.

[0067] Similar to Example 1, the coordinates of the user's viewpoint E in the world coordinate system are (e x ,e y ,e z ), the coordinates of the object to be displayed (c x ,c y ,c z Let ) be the point where the line connecting these two points intersects the projection plane (p x , p y , p z ) If so, then p y , p z This can be determined.

[0068] 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 )

[0069] Here, since p x is always set to 0, this is the formula for obtaining the projection point of the projection plane G1 of the transparent display 11. When the projection plane G2 of the display 13 is used as the projection plane, the world coordinate system is first translated parallel by the interval D between the projection planes in the x direction, and then perspective projection transformation is performed using the above formula, and the result is translated parallel in the reverse direction to return to the original world coordinate system.

[0070] The object to be displayed is displayed between the projection plane G1 and the projection plane G2, so each display point is projected onto two points on these two projection planes. Again, these two projection points are fused to implement the DFD illusion.

[0071] That is, taking the luminance at the coordinates (c x , c y , c z ) of the object as Y, the luminance y of the projection point (0, p y , p z ) on the projection plane G1 and the luminance y' of the projection point (D, p' y , p' z ) on the projection plane G2 are set as follows.

[0072] y = ((D - c x ) / D) Y y' = (c x / D) Y

[0073] These projection points overlap and fuse into one as seen by the user, and the depth direction is perceived to be c x . Again, in color display, for each component of RGB, the value is determined according to the above formula.

[0074] As a result, a three-dimensional object O is displayed between the two projection planes G1 and G2. Although this three-dimensional object O is an optical illusion, it has the characteristic of being less likely to cause discomfort or 3D sickness because it is consistent with many factors of stereoscopic vision, such as not only binocular parallax but also accommodation, convergence, and motion parallax.

[0075] The three-dimensional image display device according to the present invention enables unprecedentedly realistic stereoscopic viewing, allowing for displays that make it seem as if the real thing is there, using, for example, three-dimensional data of cultural artifacts such as clay sculptures and pottery.

[0076] Here, a cube is used as an example of an object to be displayed on the aerial image display device 1, and it is explained as being stationary in the world coordinate system. However, the present invention can be implemented even if the object undergoes arbitrary temporal changes (such as rotation or deformation) in the world coordinate system.

[0077] Furthermore, the above embodiments describe cases with eight or two display panels. However, it goes without saying that it is also possible to construct a three-dimensional display by stacking any number of display panels, such as three or four.

[0078] Furthermore, the above embodiment employs an aerial image display device using a retrotransmissive optical imaging element. However, the present invention is not limited to this, and for example, an aerial image display device using a retroreflective optical imaging element may also be employed.

[0079] 1, 2 Aerial image display device 7 Motion sensor 10 Three-dimensional display 10-1, ... 10-8 Transparent display panel 11 Transparent display 13 Display 14 Upper housing 18 Support 20 Optical plate 21 Incident surface 30, 32 Information processing device 40 Speaker 42 Face detection camera 74 Infrared camera G Aerial image area G1, ... G-8 Projection surface (image formation surface) 72 Infrared LED O Three-dimensional object

Claims

1. A three-dimensional image display device comprising: a plurality of display devices arranged parallel to each other and transparent except for at least the one located furthest back; an optical system that projects images displayed on each of the display devices into the air and displays aerial images on a plurality of projection surfaces also arranged parallel to each other; and an information processing device that supplies video signals to each of the display devices and displays images on each of the display devices, wherein the information processing device sets a three-dimensional object to be displayed in the three-dimensional space between the projection surfaces and displays an image representing this three-dimensional object on each of the display devices.

2. The three-dimensional image display device according to claim 1, further comprising a camera for detecting the viewpoint position of a user facing the three-dimensional image display device and viewing the three-dimensional image display device, wherein the information processing device receives viewpoint position information from the camera, and in conjunction with the movement of the user's viewpoint position, performs perspective projection transformation of the three-dimensional object for each of the projection surfaces with this viewpoint position as the projection center, calculates an image to be displayed on each of the projection surfaces in real time, and supplies the calculated image signal to the display device.

3. The three-dimensional image display device according to claim 2, characterized in that when performing perspective projection transformation on each point of the three-dimensional object, the perspective projection transformation is performed on both of the two projection planes flanking each point, and the brightness of each point is allocated according to the distance between each point and the projection plane.

4. A three-dimensional image display device comprising: a first and second transparent display device arranged parallel to each other; an optical system that projects an image displayed on the first display device into the air to display a first aerial image, and projects an image displayed on the second display device into the air through the first display device to display a second aerial image at a position parallel to and separated from the first aerial image; and an information processing device that supplies video signals to each of the first and second display devices and displays video on each of the first and second display devices, wherein the information processing device sets a three-dimensional object to be displayed in the space between the aerial images and displays a video representing this three-dimensional object on each of the first and second display devices.

Images