JP6775220B2 - Stereoscopic image display device - Google Patents

Description

The present invention relates to a stereoscopic image display device.

In order to realize a multi-viewpoint autostereoscopic screen with motion parallax, a method of projecting an image from a plurality of angles using a transmissive screen having a narrow diffusion angle is disclosed (Non-Patent Document 1). Further, a display device that enables smooth viewpoint switching even with motion parallax with a small number of video sources and projectors is disclosed (Patent Document 1).

The motion parallax is the parallax caused by the movement of the observer's viewpoint. In addition, the multi-viewpoint autostereoscopic image is to observe a stereoscopic image with the naked eye from different viewpoints.

Japanese Unexamined Patent Publication No. 2015-121748

Andrew Jones, Jonas Unger, Koki Nagano, Jay Busch, Xueming Yu, Hsuan-Yueh Peng, Oleg Alexander, Mark Bolas, Paul Debevec, “An Automultiscopic Projector Array for Interactive Digital Humans.” USC Institute for Creative Technologies

The method of Non-Patent Document 1 requires that projectors are installed at close intervals in order to smooth the viewpoint switching accompanying the movement of the viewpoint, and there is a problem that the required number of projectors and the video source to be projected become enormous. .. Further, Patent Document 1 has a problem that a projector needs to be installed behind a screen, the entire device becomes large, and the installation location is limited.

The present invention has been made in view of these problems, and an object of the present invention is to provide a stereoscopic image display device capable of reducing the number of projectors and saving the installation location.

In the stereoscopic image display device according to one aspect of the present embodiment, the image light from the display device at a distance of approximately a from the reflection surface at the focal distance f is reflected by the reflection surface and is at a distance of approximately b from the reflection surface. Reflection of the image light (incident light) by the reflection screen in a reflection screen having the reflection surface satisfying the relationship of (1 / a) + (1 / b) = 1 / f, which creates a spatially imaged iris surface. The horizontal brightness of the light has a diffusion characteristic that decreases linearly or monotonically as it deviates from the normal reflection direction of the incident light, and due to the diffusion characteristic, the horizontal light intensity of the spatially imaged iris surface is also from near the center. according disengaged, so as to reduce a linear or monotonically, in positions horizontally light intensity decreases in the peripheral portion of the spatial image iris plane, the center of the horizontal light intensity of the spatial image iris surface of another display device as near comes, superimposed the image light from the two or more display devices projected, the minimum value of the composite luminance of the image projected from said display device adjacent each of the two or more of said display device It is set to be higher than the average value of the maximum luminance value of the image projected from the gist of Rukoto.

According to the present invention, it is possible to provide a stereoscopic image display device capable of reducing the number of display devices (number of projectors) and saving the installation location.

It is a figure which shows the plan view of the functional configuration example of the stereoscopic image display device which concerns on 1st Embodiment of this invention. It is a figure which shows the example of the luminance distribution in two spatial imaging iris planes which can change a viewpoint smoothly. It is a figure which shows the example of the luminance distribution in two spatial imaging iris planes which cannot change the viewpoint smoothly. It is a figure which shows the example of the cross-sectional structure of the reflection screen of the stereoscopic image display apparatus shown in FIG. It is a figure which shows the example of the luminance distribution of the reflection screen shown in FIG. It is a figure which shows the synchronization part provided in the stereoscopic image display apparatus which concerns on the modification of this invention. It is a figure which shows the side view of the functional structure example of the stereoscopic image display device which concerns on the modification of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Hereinafter, the projector will be referred to as a display device.

FIG. 1 shows a plan view of a functional configuration example of the stereoscopic image display device 1 according to the embodiment.

The stereoscopic image display device 1 includes a reflection screen 10 and a plurality of display devices 20-1, 20-2, 20-3. In FIG. 1, the notation of the video signal supply unit that supplies the video source to each display device 20-1, 20-2, 20-3 is omitted.

The reflective screen 10 is a screen in which the brightness of the displayed image smoothly changes as the viewpoint moves. In the following embodiment, a "spatial imaging iris surface type screen" will be described as an example of a screen having such characteristics. The iris is a mechanism existing inside the display device, which corresponds to the aperture of the camera and adjusts the amount of light. The spatially imaged iris plane screen has a lens layer and forms a "spatial imaging iris plane" in which the iris is imaged in space. This spatially imaged iris surface has a characteristic that the brightness of the projected image smoothly transitions as the observer's viewpoint moves. The reflective screen 10 will be described in detail later.

The plurality of display devices 20-1, 20-2, and 20-3 project an image on the reflective screen 10. Adjacent display devices 20-1 and 20-2 and 20-1 and 20-3 project a part of two spatially imaged iris planes on top of each other.

A part of the spatial imaging iris surface 40-2 projected by the display device 20-2 and a part of the spatial imaging iris surface 40-1 projected by the display device 20-1 overlap. Further, a part of the spatial imaging iris surface 40-2 projected by the display device 20-2 and a part of the spatial imaging iris surface 40-3 projected by the display device 20-3 overlap.

According to the stereoscopic image display device 1 of the present embodiment, the video source is projected from the front onto the reflective screen 10 having a characteristic that the brightness changes smoothly as the viewpoint moves, so that the conventional (transmissive screen + rear projector) Compared to the method, the number of display devices can be reduced and the installation location can be saved.

(Configuration of stereoscopic image display device)
The configuration of the stereoscopic image display device 1 will be described with reference to FIG. In FIG. 1, the horizontal direction of the reflection screen 10 as viewed from the observer is the x direction, the vertical direction is the y direction, and the thickness direction (depth direction) is the z direction. Here, the observer's side is referred to as the front side.

In this example, the number of display devices is indicated by three. The number of display devices may be two or more. In the following description, when it is not necessary to specify the position of the display device, it is referred to as "display device 20". The same applies to other reference codes.

The display devices 20-1, 20-2, and 20-3 are arranged at a distance a from the front of the reflective screen 10. The central display device 20-2 projects the projection 30-2 onto the reflective screen 10. The projected light of the display device 20-2 forms the spatial imaging iris surface 40-2 at a position d away from the surface of the reflective screen 10 by the reflective screen 10.

The display devices 20-1 are arranged side by side at a predetermined interval in the + x direction from the central display device 20-2. The display device 20-1 projects the projection 30-1 on the reflective screen 10.
The projected light of the display device 20-1 forms the spatial imaging iris surface 40-1 adjacent to the spatial imaging iris surface 40-2 in the −x direction.

Although the display device 20-1 is described so as having an angle in the direction of the projection 30-1, it is not necessary to give an angle to the projected light projected from the display device 20-1. If the image projection area from the display device 20 includes the entire reflection screen 10, the display device 20 does not have to have an angle.

The display device 20-3 is arranged at a position symmetrical with the display device 20-1 with the display device 20-2 interposed therebetween. The display device 20-3 projects the projection 30-3 on the reflection screen 10. The projected light of the display device 20-3 forms the spatial imaging iris surface 40-3 at the position on the + x side of the spatial imaging iris surface 40-2.

The distance d in the z-axis direction (distance d in FIG. 1) at which the spatially imaged iris planes 40-1, 40-2, and 40-3 are imaged is such that the focal length of the reflection screen 10 is f and the display device 20 and the display device 20. When the distance between the reflective screens 10 is a, the equation (1 / a) + (1 / d) = 1 / f is satisfied. Both ends of the central spatially imaged iris surface 40-2 in the x direction overlap with a part of the adjacent spatially imaged iris surfaces 40-1, 40-3, respectively.

The + x-direction end of the spatially imaged iris surface 40-2 overlaps the −x direction end of the spatially imaged iris surface 40-3. Further, the end portion of the spatial imaging iris surface 40-2 in the −x direction overlaps with the end portion of the spatial imaging iris surface 40-1 in the + x direction.

Next, the display method of this embodiment will be described.

(Display method)
The display method of the present embodiment is a display method performed by the stereoscopic image display device 1, and the stereoscopic image display device 1 has a reflection screen 10 having a characteristic that a change in brightness accompanying movement of a viewpoint smoothly transitions, and reflection. A plurality of display devices 20-1, 20-2, 20-3 for projecting an image on the screen 10 are provided, and in the display method, two spatially imaged iris surfaces 40-2 projected from adjacent display devices 20. And 40-1, and a part of 40-2 and 40-3 are projected on top of each other.

The reflective screen 10 has one peak in the brightness distribution in the spatially imaged iris plane to be imaged, and the viewpoint is viewed in either the x direction or the −x direction from the position of the viewpoint (observer's eye) where the brightness peaks. It is designed so that the brightness attenuates smoothly even when moving. For example, in the spatial imaging iris surface 40-2 by the display device 20-2 projecting from the front of the reflective screen 10, the brightness of the projection 30-2 is the highest at the center of the spatial imaging iris surface 40-2, and x It gradually decreases regardless of whether the viewpoint is moved in the direction or the -x direction. Further, the projection 30-2 cannot be seen from both outsides of the spatial imaging iris surface 40-2 in the ± x direction.

The brightness of the projection 30-1 on the spatial imaging iris surface 40-1 on the −x direction side of the spatial imaging iris surface 40-2 is within the spatial imaging iris surface 40-1 as in the projection 30-2. It has one peak in, and it decreases regardless of which viewpoint moves in the ± x direction from the viewpoint that becomes the peak.

Further, when the viewpoint deviates from the spatially imaged iris plane 40-1 to both outer sides in the ± x direction, the projection 30-1 is not observed. Therefore, when the distance between the projection 30-2 and the projection 30-1 is widened and the spatial imaging iris planes 40 do not overlap, the projection 30-2 and the projection 30-1 are switched according to the viewpoint position, and both. Cannot be observed at the same time.

On the other hand, when the space between the spatial imaging iris surface 40-2 and the spatial imaging iris surface 40-1 is narrowed and a range in which the spatial imaging iris surfaces 40-2, 40-1 overlap is provided, projection is performed in this overlapping range. The object 30-2 and the projection 30-1 can be seen at the same time. That is, the projection 30-2 and the projection 30-1 are mixed (blended) and viewed.

Here, it is assumed that an image of an object taken from the front is projected on the projection 30-2, and an image of an object taken from the left is projected on the projection 30-1. That is, when the observer looks at the reflection screen 10 while moving from the center of the central spatial imaging iris surface 40-2 to the spatial imaging iris surface 40-1, the observer looks at the object so as to wrap around from the front to the left. You will perceive the object.

At this time, the parallax distance ν between the projection 30-2 observed in the spatially imaged iris surface 40-2 and the projection 30-2 observed in the spatially imaged iris surface 40-1 is the fusion limit angle A. By doing the following, the two spatially imaged iris planes 40-2 and 40-1 are smoothly fused according to the movement of the viewpoint, and the image of the intermediate viewpoint between the projection 30-2 and the projection 30-1 is reproduced. be able to. As a result, the observer perceives an image having binocular parallax, which enables autostereoscopic viewing. The relationship between the parallax distance ν between the projections, the distance d from the reflection screen 10 to the spatial imaging iris surface 40, and the fusion limit angle A is expressed by the following equation.

The fusion limit angle A is an angular interval in which two adjacent edges are observed to be fused without being separated, and is 3 min (of arc) to 8 min (of arc) (reference: H. Takada, S. Suyama and). M. Date, valuation of the Fusional Limit between the Front and Rear Images in Depth-Fused 3-D Visual Illusion, ”IEICE Trans. On Electron., Vol. E89-C, No. 3, pp. 429-433 (2006) )). In the region where the two spatially imaged iris surfaces 40 overlap each other in the two adjacent spatially imaged iris surfaces 40, the two spatially imaged iris surfaces 40 are observed at the same time, but the spatial image is formed. If the distance between the iris surfaces 40 is less than or equal to this fusion distance, the spatially imaged iris surfaces 40 are blended and an intermediate viewpoint between the two spatially imaged iris surfaces 40 is perceived. The same applies to the relationship between and the spatially imaged illusion surface 40-3.

Assuming that the projection 30-3 is an image of an object taken from the right direction, the object is viewed from the right direction within the range where the spatial imaging iris surface 40-2 and the spatial imaging iris surface 40-3 overlap. It is perceived as a stereoscopic image.

In order to smooth the switching of the image due to the movement of the viewpoint between the spatial imaging iris surface 40-2 and the spatial imaging iris surface 40-3, the range in which the spatial imaging iris surfaces 40-2 and 40-3 overlap is smooth. The arrangement interval of the display device 20 is set so that the combined luminance value in the above image above is higher than the average value of the peak luminance values of the spatially imaged iris surfaces 40-2 and 40-3. That is, the minimum value of the combined brightness of the images projected from the adjacent display devices 20 is set to be higher than the average value of the maximum brightness values of the images projected from each of the two or more display devices 20. ..

FIG. 2 shows an example of the brightness distribution set to such a combined brightness value. The horizontal axis of FIG. 2 is the viewpoint B [degree], and the vertical axis is the relative brightness. In FIG. 2, the broken line is, for example, the luminance distribution of the spatially imaged iris surface 40-1. The alternate long and short dash line is, for example, the luminance distribution of the spatially imaged iris surface 40-2. The thick solid line is the combined brightness of the two spatially imaged iris planes 40-1 and 40-2.

The combined brightness value of the two spatially imaged iris surfaces 40-1 and 40-2 is larger than the average brightness of the peak values (center points of the arrows) of the two spatially imaged iris surfaces 40-2 and 40-1. It's getting higher. By setting such a composite luminance value, the observer can perceive a smooth luminance change by moving the viewpoint in the spatial imaging iris plane. Further, if the tail portion (α, β in FIG. 2) of the brightness distribution of the spatially imaged iris surface 40 does not become 0, noise occurs, which leads to quality deterioration of the synthesized image. However, by setting the combined luminance values to be higher than the average of the peak luminance values, the influence of noise can be relatively reduced and the image quality can be improved. That is, according to the display method of the present embodiment, it is possible to smoothly perform multi-viewpoint autostereoscopic projection accompanied by motion parallax. This is the same even when the height of the peak value, the degree of spread of the hem, and the left-right symmetry in the brightness distribution of the two adjacent spatially imaged iris surfaces 40 are different.

FIG. 3 shows an example of the luminance distribution of the comparative example. The relationship between the horizontal axis and the vertical axis of FIG. 3 and the relationship of each characteristic are the same as those of FIG.

In FIG. 3, the combined luminance value of the two projections 30-1 and 30-2 is lower than the average luminance value at the intermediate position between the two spatially imaged iris planes 40-2 and 40-1. In this case, as the viewpoint moves to the intermediate position, the overall brightness decreases, and the brightness of the adjacent viewpoint also decreases, so that smooth viewpoint interpolation cannot be performed.

Next, the reflective screen 10 will be described.

(Reflective screen)
FIG. 4 shows an example of the cross-sectional structure of the reflective screen 10. The reflective screen 10 has a layer structure of a holding plate 10a, a reflective layer 10b, a UV-polymerized Fresnel lens layer 10c, and an anisotropic diffusion layer 10d.

The holding plate 10a is a substrate that maintains the flatness of the reflective screen 10, and is made of, for example, a plastic plate or the like. A reflective layer 10b is formed on the front side of the holding plate 10a.

The reflective layer 10b is made of a metal having a high reflectance such as aluminum, silver, and nickel. A UV-polymerized Fresnel lens layer 10c is formed on the front side of the reflective layer 10b.

The front side of the UV-polymerized Fresnel lens layer 10c is flat, and the back side forms a Fresnel lens surface, which is made of a resin such as epoxy acrylic rate. An anisotropic diffusion layer 10d is formed on the front side of the UV-polymerized Fresnel lens layer 10c.

Anisotropic diffusion is a diffusion layer in which the diffusion angle of light diffused by the diffusion layer has different characteristics in two orthogonal directions having a specific relationship with the surface shape of the diffusion layer. The anisotropic diffusion layer 10d has, for example, a Gaussian distribution of luminance within the diffusion angle range.

FIG. 5 shows an example of the brightness distribution of the reflection screen 10. The horizontal axis of FIG. 5 is the viewpoint B [degree], and the vertical axis is the brightness [cd / m ² ].

The viewpoint B [degree] is in the perpendicular direction. It shows a characteristic that the brightness gradually decreases with respect to a change in the incident angle θ in the ± direction centered on 0 degrees. In this example, the brightness is halved when the incident angle θ changes by about 7 degrees.

By using the reflective screen 10 illustrated in FIG. 4, the characteristics of the mixed combined luminance values shown in FIG. 2 can be realized.

(Modification example 1)
FIG. 6 shows a part of the functional configuration example of the modified example 1 in which the stereoscopic image display device 1 is modified. Modification 1 includes a synchronization unit 60. Modification 1 is different from the stereoscopic image display device 1 (FIG. 1) in that it includes a synchronization unit 60.

The synchronization unit 60 synchronizes the video signals corresponding to the plurality of display devices 20 respectively. Video sources are supplied to the synchronization unit 60 from the video signal supply units 50-1, 50-2, and 50-3, respectively.

The video source supplied from the video signal supply unit 50-1 is projected from the display device 20-1 onto the reflection screen 10. The video source supplied from the video signal supply unit 50-2 is projected from the display device 20-2 onto the reflection screen 10. The video source supplied from the video signal supply unit 50-3 is projected from the display device 20-3 onto the reflection screen 10.

When the video source supplied from the video signal supply unit 50 is, for example, a moving image, the synchronization unit 60 synchronizes each video source. When the video source is, for example, a moving image having a frame rate of 60 f / s, the synchronization unit 60 synchronizes each frame.

By synchronizing each frame, it is possible to obtain the above perceptual effect even in a moving image. Further, the synchronization unit 60 and the video signal supply unit 50 may exist over the network, and can also function as a system for delivering stereoscopic images taken at a remote location in real time.

(Modification 2)
FIG. 7 shows a functional configuration example of the modified example 2 in which the stereoscopic image display device 1 is modified. FIG. 7 is a side view of the stereoscopic image display device 1 as viewed from the side of the display device 20-1.

The reflective screen 10 of the second modification has a characteristic of vertical diffusion. Vertical diffusion is to diffuse the projected light in the y direction. That is, the reflective screen 10 of the second modification has a wide diffusion characteristic in the vertical direction.

By having the characteristic of vertical diffusion, the spatial imaging iris surface 40-3 can be extended in the ± y direction. As a result, even if the observer's viewpoint moves in the y direction, a smooth change in brightness in the x-axis direction can be perceived, so that it is possible to deal with differences in the height of the observer and differences in the viewing position in the vertical direction. Further, even if the display device 20 is installed on the floor or ceiling and projected from diagonally above or below the reflective screen 10, the spatial imaging iris surface 40 can be formed at the front position, so that the equipment is placed in the observation range. It is also possible to use a display device with no configuration or short focus.

As described above, according to the stereoscopic image display device 1 of the present embodiment, since it is a front projection type, the number of display devices can be reduced as compared with the method of arranging the display devices behind the conventional transmissive screen, and the installation can be performed. It has the effect of saving space. Further, the stereoscopic image display device 1 can smoothly perceive the change in brightness accompanying the movement of the viewpoint.

Further, in the present embodiment, no special video processing is required. For example, the above perceptual effect can be obtained simply by projecting the video source captured by the camera as it is from the display device 20.

In the above description, the number of display devices 20 is three, but the number of display devices 20 may be two or more. As the number of display devices 20 increases, the projection range can be expanded in the x direction. Further, the examples described in the modified examples 1 and 2 can be combined with each other. In addition, it is possible to increase the number of viewpoints in the vertical direction by rotating the installation of the stereoscopic image display device 1 by 90 degrees or the like. Moreover, although the example in the x-axis direction has been described above, when the vertical diffusion is not used, the projection that smoothes the viewpoint movement is also possible in the y-axis direction. In that case, by installing the display device 20 in the x-axis direction and the y-axis direction, the image viewed from the viewpoint position can be perceived even if the observer moves up, down, left, and right.

Further, in the above description, the reflection screen 10 is a screen forming the spatial imaging iris surface 40, and the brightness distribution is Gaussian. However, the brightness distribution may be linear. In short, a reflective screen having a brightness distribution in which the brightness changes smoothly as the viewpoint moves can be used as a substitute.

As described above, the present invention is not limited to the above-described embodiment, and can be modified within the scope of the gist thereof.

Since this embodiment is easy to install and has high brightness, it can be applied to, for example, an outdoor signboard, a display board for real-time communication, and a notation board for entertainment and amusement, and is widely used in the field of communication. It is possible.

1: Stereoscopic image display device 10: Reflective screen 10a: Holding plate 10b: Reflective layer 10c: UV polymerized Fresnel lens layer 10d: Anisotropic diffusion layer 20-1, 20-2, 20-3: Display device 30-1, 30-2, 30-3: Projections 40-1, 40-2, 40-3: Spatial imaging iris planes 50-1, 50-2, 50-3: Video signal supply unit 60: Synchronization unit ν: Parallax Interval d: Interval (distance)
A: Fusion limit angle

Claims (3)

Image light from a display device at a distance of approximately a from the reflection surface at the focal length f is reflected by the reflection surface to form a spatially imaged iris surface at a distance of approximately b from the reflection surface (1 / a). In a reflective screen having the reflective surface satisfying the relationship of + (1 / b) = 1 / f,
The horizontal brightness of the reflected light by the reflection screen of the image light (incident light) has a diffusion characteristic that decreases linearly or monotonically as it deviates from the specular reflection direction of the incident light.
Due to the diffusion characteristics, the horizontal light intensity of the spatially imaged iris surface also decreases linearly or monotonically as it deviates from the vicinity of the center.
A position horizontally light intensity of the peripheral portion of the spatial image iris plane decreases, the should come near the center of the horizontal light intensity of the spatial image iris surface of another display device, two or more display devices The above-mentioned image light from is superimposed and projected ,
The minimum value of the composite luminance of the image projected from said display device adjacent, that that will be set to be higher than the average value of the maximum luminance value of the image projected from each of two or more of said display device A featured stereoscopic image display device. The stereoscopic image display device according to claim 1, wherein the reflective screen has a wide diffusion characteristic in the vertical direction. The stereoscopic image display device according to claim 1 or 2 , further comprising a synchronization unit that synchronizes video signals corresponding to each of the plurality of display devices.

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