JP7322490B2 - 3D image display system and usage method thereof, 3D image display display and usage method thereof, 3D image display display pattern calculation method - Google Patents

Description

Embodiments of the present invention relate to three-dimensional image display systems, three-dimensional image display displays, methods of using them, and methods of calculating display patterns.

Knowing each other's feelings is important for communication between family members, close friends, or even in the world of politics and business. In the non-verbal part, it is necessary to communicate the distance between conversations and the sense of distance in personal space without discomfort. .

Conversation intervals can be achieved with 5G low-latency technology due to advances in communication technology, and accurate measurement of distance can be achieved with 3D measurement technology such as TOF (Time of Flight). . However, there is no technology for displaying the sense of distance without discomfort.

Various methods have been studied as methods for displaying a three-dimensional image. For example, head-up displays, polarizing glasses, and liquid crystal shutter glasses, which require glasses to be worn on the head, or parallax barrier, lenticular, etc., which allow two eyes to observe different parallaxes without glasses. There was something that displayed an image.

Since the above methods create a three-dimensional effect only by parallax, contradiction with other visual physiology such as convergence and focus adjustment causes fatigue and sickness, and acquisition of a sense of distance necessary for communication. was inadequate for For example, in a study by Nishimura et al. of Akita University, there was a significant increase in the number of subjective symptoms related to drowsiness, sluggishness, and physical discomfort before and after playing a 3D game. mentions the adverse effects of

In order to overcome the above-mentioned drawbacks, methods have been devised that are consistent with vergence and focus adjustment. For example, a super multi-view display or a display that uses a microlens array to record a light field (direction information and intensity distribution on the imaging surface of light rays incident on the imaging surface of a digital camera) and reproduce the recorded light field. , and a static display type light field display in which a liquid crystal panel or the like is superimposed has been proposed.

FIG. 20 is a schematic cross-sectional view illustrating a conventional configuration of a light field display using a microlens array, and FIG. 21 is a schematic cross-sectional view illustrating a conventional configuration of a static display type light field display in which liquid crystal panels are stacked. (for example, Non-Patent Document 1).

Further, according to the stereoscopic image display device described in Patent Document 1, by sufficiently increasing the number of viewpoints (super multiview), human stereoscopic perception includes binocular parallax, focus adjustment, convergence, and motion parallax. can satisfy the four factors of

The super multiview display and light field display described above realize natural focus adjustment and convergence by reproducing light rays in a size smaller than the size of the pupil. However, because the light rays are controlled in such a small area, the effect of diffraction causes the blurring to increase as the distance from the display surface increases. Couldn't reproduce.

A hologram is a three-dimensional display (stereoscopic image display) capable of reproducing a space with depth. Since the hologram reproduces the wavefront of light as it is, it is theoretically possible to reproduce a space with depth by reproducing it with a laser beam. However, analog holograms cannot be photographed if the subject vibrates, so it is only possible to photograph the subject on a table that does not vibrate, such as an anti-vibration table, and it is difficult to photograph the space itself.

In addition, digital holograms that create and reproduce interference fringe patterns calculated by a computer must sample the object to be reproduced on the order of microns and then calculate the wavefront that propagates. Recreating a large space has traditionally been impractical because it requires an enormous amount of calculation.

The target space in this application is not a space in which an object is near the display like a conventional three-dimensional display (stereoscopic image display device), but is, for example, in a room or in a park. The display is used as a window, and an area away from the display surface is displayed as if observing the outside through the window.

Edward Hall, an American cultural anthropologist, classifies interpersonal distance (personal space) between people into the following four distance zones.

1) Close distance: The distance to the other party is 0 to 0.45 m, and the distance is such that the body temperature and smell of the other party can be detected. At a distance with a very intimate partner, communication is mainly through skin-to-skin contact such as holding hands and scent.
2) Individual distance: The distance to the other person is 0.45 to 1.2 m, which is the distance to maintain one's independence. If you or the other person stretches out your hand, you can touch it, and it is the distance to a close person such as a friend.
3) Social distance: The distance between the other person is 1.2 to 3.6m, which is a distance where you cannot touch the other person, and is suitable for communication in formal situations such as conversations between colleagues at work. is.
4) Public distance: The distance between the other party is 3.6m or more, which is inappropriate for communication between two parties, and is the distance for speeches and lectures.

A space where a person lives mainly while communicating with others ranges from an individual distance to a social distance, and ranges from 0.45 m to 3.6 m. This distance range is called an appropriate communication distance in the present application.

In addition, according to research by Miyazaki et al. of Tokyo Women's University, it is difficult to recognize the facial expression of the other person when the distance is 7 m or more in the case of visual acuity of 1.0. In this case, the appropriate communication distance may be replaced with 0.45 to 7 m by adding the distance at which communication can be achieved while reading the person's facial expression.
However, in order to observe facial expressions at a distance of 3.6m, a resolution (no blur) equivalent to 0.5 or better is usually required, and it is presumed that at least a resolution equivalent to 0.3 or better is required. It can be done (from the materials of the 71st meeting of the Japanese Psychological Association (2007)).

However, there has not existed a technology that can display an object at an appropriate communication distance as described above without contradiction with visual physiological phenomena such as focus adjustment or convergence and without blurring. The invention of the present application is a three-dimensional object that can be reproduced without blurring or discomfort, even if the object is in the appropriate communication distance range (hereinafter also referred to as communication space) and is distant from the display surface, after acquiring a natural sense of distance. It relates to an image display system.

Generally, in a display that allows focus adjustment, as shown in FIG. 17, the observer observes the space in front of and behind the display surface through the display surface, and the direction is the same as the light spreading from the reproduction point, which is the point object to be reproduced. is reproduced in a size smaller than the observer's pupil, the observer can observe as if there were a point light source in space.

However, as shown in FIG. 18, light rays reproduced from the display are, strictly speaking, spread light due to various causes, which causes blurring of the reproduced image. In particular, when the element cell of the display that determines the direction of the light beam is small, the light spreads around the outside of the aperture due to the influence of diffraction using the element cell as the aperture, resulting in blurring.

The spread of diffraction due to an aperture can be approximated as Fraunhofer diffraction at a position away from the display surface, and in the case of a circular aperture, the spread angle can be obtained from the size of the Airy disk (the bright area that appears in the center of the diffraction pattern). can be done. That is, if the distance between the minimum dark ring that can be formed in the far field away from the circular aperture and the optical axis is represented by the divergence angle θ of a ray parallel to the optical axis and passing through the end surface of the circular aperture (see FIG. 19),
θ=1.22×λ/d (Formula 1)
becomes. where λ is the wavelength of light and d is the diameter of the circular aperture.

Since the aperture as described above is a unit of area on the display that defines the direction of light rays, it is hereinafter referred to as an "element cell". For example, in a light field display using a microlens array (FIG. 20), one lens corresponds to an element cell. In the case of a static display type light field display (FIG. 21) in which liquid crystal panels and the like are superimposed, the pixels of the display used are the element cells.

Since the light field display controls the direction of light rays for each element cell, the element cells must be sufficiently smaller than the observer's pupil in order to have a focusing function. Since the size of the human pupil is generally about 2 to 8 mm, if the size of the element cell is 0.3 mm and the wavelength of light is 500 nm, the divergence angle of the ray is given by (Equation 1):
θ=1.22×500×10 ⁻⁶ /0.3≈2.03×10 ⁻³ (rad)
≈ 0.12 (degrees)
becomes. In other words, at a position L=3.6 m in FIG.
3600×tan (0.12°)×2≈15 (mm)
As a result, the blur with a length of about 15 mm spreads.

For example, if the face of a person at a distance of 3.6 m is blurred by about 15 mm, the person can be recognized, but it is difficult to read the facial expression.
In recent years, with the development of artificial intelligence technology and speech synthesis technology, there are increasing cases of communicating with non-existent people and characters created in virtual space. For example, there is a smartphone application developed by Sony Music Communications that allows you to talk with anime characters. However, these can only be displayed on screens such as smartphones and PCs, and it is not possible to communicate in an appropriate communication space.

In digital holograms, the object, which is the subject, is generally regarded as a collection of point light sources, and the wavefront that reaches the display surface from each point overlaps the wavefront of the reference light, and the intensity is recorded to create a hologram pattern. Since hologram reproduction utilizes the diffraction of light, the hologram pattern on the display surface must be as fine as about 1 μm, and generally the object side must also be sampled with the same fineness (see, for example, Patent Document 2). Therefore, when reproducing a large object that exists in the appropriate communication space, the number of light spots is enormous.

For example, when reproducing a space extending 3.6 m deep at an angle of ±30 degrees, the radius of the space is 3.6×tan (30 degrees)≈2.078 m. If a circle with a radius of 2.078 m is sampled at 1 μm, the number of points to be sampled is about 14 trillion, which is a huge amount of sampling. This is a sampling point of one plane with a depth of 3.6m, and it is easy to imagine that the amount of calculation will be astronomical if you sample each object existing at various depths at 1 μm intervals and calculate the wavefront from there. can. Furthermore, since all objects are expressed as a collection of point light sources, there is also the drawback that it is difficult to express glossy or transparent objects.

As described above, in order to reproduce the appropriate communication space, the conventional light field display, in which the direction of light rays is determined for each element, causes a large blurring due to the influence of diffraction. , there is a problem that a huge amount of calculation is required, there is a limit to the expression that can be displayed, and it is unrealistic to realize it by either method.

JP 2007-17634 A Japanese Patent No. 6210549

Takafumi Koike, Electronic Display Ergonomics Symposium 2018 https://home.jeita.or.jp/device/lirec/symposium/fpd/pdf/2018_2a.pdf

The embodiments of the present invention have been made in view of the above problems, and provide a natural sense of distance and blur in a distance space of 0.45 m to 7 m, where people live while communicating with others. It is possible to provide a three-dimensional image display system and a method of using the same, which enables display without any image.

In order to solve the above problems, the invention according to claim 1 is a three-dimensional image display system comprising at least a stereoscopic camera and a three-dimensional image display,
The stereoscopic camera has a function of acquiring information on the incident direction and intensity of light rays incident on the imaging surface from the object to be photographed,
The three-dimensional image display has at least an arithmetic function, a display function, and a light control function, and comprises a plurality of arranged element cells,
the arithmetic function has a function of calculating the direction and intensity of light rays to be reproduced for each of the plurality of element cells after receiving the information from the stereoscopic camera;
the plurality of elemental cells displaying a three-dimensional image of the object by reproducing the calculated ray directions and intensities;
the size of the plurality of element cells is larger than the pitch at which the plurality of element cells are arranged;
When the size of the plurality of element cells is d, d is 2.1 mm or more, and when the pitch at which the plurality of element cells are arranged is p, p is 1.2 mm or less,
In the element cells, interference fringes of spherical waves diverging from intersections of a plurality of light rays in different directions starting from the centers of the element cells and the object and the reference light are recorded.
A three-dimensional image display system characterized by:

In the invention according to claim 2, a storage function for storing the result of calculation by the calculation function,
2. The three-dimensional image display system according to claim 1, further comprising either or both of a communication function capable of communicating with the outside of the system wirelessly or by wire.

3. The three-dimensional image display according to claim 1 or 2, wherein the minimum angular resolution of the rays reproduced from the plurality of element cells is 0.033 degrees or less. It is a system.

In the invention according to claim 4 , the three-dimensional image display constitutes a head-mounted display including an eyepiece, and when the magnification of the eyepiece is r,
1 to 1, characterized in that a size d of the plurality of element cells is 2.1/r mm or more, and a pitch p at which the plurality of element cells are arranged is 1.2/r mm or less. 3. The three-dimensional image display system according to any one of 3 .

The invention according to claim 5 is characterized in that the size d of the plurality of element cells is 2.1 mm or more, and the pitch p at which the plurality of element cells are arranged is 0.5 mm or less. A three-dimensional image display system according to any one of Items 1 to 4 .

In the invention according to claim 6 , the three-dimensional image display constitutes a head-mounted display including an eyepiece, and when the magnification of the eyepiece is r,
1 to 1, characterized in that a size d of the plurality of element cells is 2.1/r mm or more, and a pitch p at which the plurality of element cells are arranged is 0.5/r mm or less. 6. The three-dimensional image display system according to any one of 5 .

According to a seventh aspect of the present invention, the three-dimensional image is obtained by obtaining, in the arithmetic function, intersections between a plurality of light rays in different directions starting from the center of each element cell and an object, and wavefronts from the respective intersections. is calculated, the interference fringes with the reference light are calculated for the calculated sum data, the interference fringes are displayed on the display function, and displayed by illuminating the reproduction light The three-dimensional image display system according to any one of claims 1 to 6 , characterized by:

The invention according to claim 8 is a method for using the three-dimensional image display system according to any one of claims 1 to 7 ,
A method of using a three-dimensional image display system, wherein the distance from the display surface of the three-dimensional image display to the part of the three-dimensional image of the object is 0.45 to 7 m. .

The invention according to claim 9 is a method for using the three-dimensional image display system according to any one of claims 1 to 7 ,
A method of using a three-dimensional image display system, wherein the distance from the display surface of the three-dimensional image display to the part of the three-dimensional image of the object is 1.2 to 7 m. .

A tenth aspect of the invention is characterized in that the reproduced light rays are stored in a memory function, and later, the observer observes the three-dimensional image by reproducing the memory using the three-dimensional image display. A method of using the three-dimensional image display system according to claim 8 or 9 , wherein:

The invention according to claim 11 is characterized in that two or more of the three-dimensional image display systems according to any one of claims 1 to 7 are installed at two or more locations separated from each other, and the two systems are connected via a communication function. characterized by connecting the system or more with a digital transmission network and transmitting the three-dimensional image,
A method for using the three-dimensional image display system according to any one of claims 8 to 10 .

According to a twelfth aspect of the present invention, there is provided a three-dimensional image display, comprising a collection of a plurality of element cells, wherein d is 2.1 mm or more, and the plurality of When the pitch at which the element cells are arranged is p, p is 1.2 mm or less ,
In the element cells, interference fringes of the reference light and spherical waves diverging from intersections of a plurality of light rays in different directions starting from the center of each element cell and an object to be photographed are recorded.
This is a three-dimensional image display display characterized by:

In the thirteenth aspect of the present invention, the three-dimensional image display constitutes a head-mounted display including an eyepiece, and when the magnification of the eyepiece is r,
12. The method according to claim 11 , wherein the size d of the plurality of element cells is 2.1/r mm or more, and the pitch p at which the plurality of element cells are arranged is 1.2/r mm or less. It is the three-dimensional image display display described above.

The invention according to claim 14 is characterized in that the size d of the plurality of element cells is 2.1 mm or more, and the pitch p at which the plurality of element cells are arranged is 0.5 mm or less. Item 12 or 13 , which is a three-dimensional image display.

In the fifteenth aspect of the present invention, the three-dimensional image display constitutes a head-mounted display including an eyepiece, and when the magnification of the eyepiece is r,
12. A size d of the plurality of element cells is 2.1/r mm or more, and a pitch p at which the plurality of element cells are arranged is 0.5/r mm or less. 13 or the three-dimensional image display display described in 13 above.

In the invention according to claim 16 , the three-dimensional image display has at least a computing function,
In the arithmetic function, intersections between a plurality of light rays in different directions starting from the center of each element cell and the object are obtained, the sum of complex amplitudes of wavefronts from each intersection is calculated, and the calculated sum is calculated. 12. An interference fringe with reference light is calculated for the data, the interference fringe is displayed on a display function, and a three-dimensional image of the object is displayed by illuminating the reproduction light. 16. The three-dimensional image display according to any one of 15 to 15 .

The invention according to claim 17 is a method for using the three-dimensional image display according to any one of claims 12 to 16 , wherein one of the three-dimensional images of the object is displayed from the display surface of the three-dimensional image display. The method of using the three-dimensional image display is characterized in that the distance to the part is 0.45 to 7 m.

The invention according to claim 18 is a method for using the three-dimensional image display according to any one of claims 12 to 16 , wherein one of the three-dimensional images of the object is displayed from the display surface of the three-dimensional image display. The method of using the three-dimensional image display is characterized in that the distance to the part is 1.2 to 7 m.

The invention according to claim 19 is a method for using the three-dimensional image display according to claim 17 or 18 , wherein at least one of the three-dimensional images of the object is a person. .

The invention according to claim 20 is a method for using the three-dimensional image display according to any one of claims 16 to 18 ,
A three-dimensional image display, characterized in that reproduced light rays are stored in a memory function, and later, an observer observes a three-dimensional image by reproducing said memory using said three-dimensional image display. How to use.

According to the embodiment of the present invention, in a distance space of 0.45m to 3.6m where people live while communicating with others, a natural sense of distance can be obtained and display without blurring is possible3. A dimensional image display system and method of use thereof are provided.

1 is a block diagram showing the configuration of a first embodiment of a three-dimensional image display system of the present invention; FIG. 1 is a conceptual diagram and a plan view showing how to use the first embodiment of the three-dimensional image display system of the present invention; FIG. FIG. 4 is a block diagram showing the configuration of a second embodiment of the three-dimensional image display system of the present invention; FIG. 10 is a conceptual diagram and a plan view showing how to use the 3D image display system of the second embodiment according to the embodiment of the present invention; FIG. 10 is a characteristic diagram obtained by calculating the length of blur due to diffraction with the size of an element cell as a parameter and the distance from the display as the horizontal axis. FIG. 10 is a characteristic diagram obtained by calculating the resolution on the retina (circle of confusion diameter) when viewing an object, using the pitch of the element cells as a parameter and the distance from the display as the horizontal axis. FIG. 4 is a schematic diagram of a case where the element cell pitch is smaller than the element cell size (p<d), according to the embodiment of the present invention, and is a configuration diagram of the hologram viewed from the front. FIG. 4 is a schematic diagram in the case where the element cell pitch is smaller than the element cell size (p<d), according to the embodiment of the three-dimensional image display of the present invention, and is an explanatory diagram when the hologram is viewed from the side. 1 is a configuration diagram illustrating a conventional element cell for comparison; FIG. FIG. 4 is a configuration diagram illustrating element cells having a relationship that the element cell pitch is smaller than the element cell size (p<d) according to the embodiment of the three-dimensional image display of the present invention; Fig. 10 is another example of an element cell having a relationship in which the element cell pitch is smaller than the element cell size (p < d) according to the embodiment of the three-dimensional image display of the present invention, and an element cell made of a diffraction grating is used as a coarse display device. It is a block diagram which illustrates the case of using. FIG. 4 is a conceptual diagram when an object point A is reproduced by a holographic stereogram in which element cells whose pitch is smaller than the size of the element cells are arranged on the display surface. FIG. 4 is a conceptual diagram for explaining how the brightness of light rays reproduced from element cells is bright at the center and dark at the periphery. According to the embodiment of the three-dimensional image display system of the present invention, the object point A is displayed by a holographic stereogram in which element cells recording interference fringes of a spherical wave diverging from the object point A and the reference light are arranged on the display surface. FIG. 4 is a conceptual diagram when playing back; FIG. 15 is a conceptual diagram for explaining how a plurality of objects are reproduced by the method of FIG. 14; FIG. 4 is a conceptual diagram for explaining a method of calculating hologram reconstruction data by applying a ray tracing method; FIG. 4 is a schematic diagram showing how an observer observes a reproduction point through the display surface; FIG. 10 is a schematic diagram showing a state in which a light beam reproduced from a display becomes light with a spread, and a reproduced point is blurred. FIG. 4 is a schematic diagram for explaining the spread angle of Fraunhofer diffraction by a circular aperture and its magnitude. 1 is a schematic cross-sectional view illustrating the configuration of a conventional light field display using a microlens array; FIG. 1 is a schematic cross-sectional view illustrating the configuration of a conventional static display type light field display in which liquid crystal panels are stacked; FIG. 1 is a block diagram showing the configuration of an embodiment of a three-dimensional image display of the present invention; FIG. 1 is a conceptual diagram and a plan view showing a usage example of an embodiment of a three-dimensional image display according to the present invention; FIG. Fig. 2 is a flow chart showing an example of a method for calculating a three-dimensional image display display pattern of the present invention;

A three-dimensional image display system according to an embodiment of the present invention will be described below with reference to the drawings. A three-dimensional image display system can be implemented with optical devices and electrical circuits. In each drawing, the thickness and ratio of the constituent elements may be exaggerated for clarity, and the number of constituent elements may be reduced. Moreover, the present invention is not limited to the following embodiments as they are, and can be embodied by appropriate combinations and modifications without departing from the spirit of the present invention.

FIG. 1 is a block diagram showing the configuration of a three-dimensional image display system 10 according to a first embodiment of the three-dimensional image display system of the present invention. The three-dimensional image display system 10 of the first embodiment acquires three-dimensional information of an object, which is a subject photographed by a stereoscopic camera, and transfers it to an arithmetic function. The three-dimensional information includes at least the incident direction and intensity of light rays incident on the imaging surface from the object, and may be obtained from two or more parallax image sequences or a combination of a two-dimensional image and a range image. Any spatial information about the desired object may be used.

Various methods are conceivable for a stereoscopic camera for acquiring three-dimensional information. For example, a method of comparing and measuring images taken by two cameras, a method of analyzing a pattern projected onto an object to be photographed, a TOF (Time Of Flight) method of measuring distance by measuring the time of flight of light, etc. be. Any method may be used as long as the range of suitable communication distance can be measured with the required resolution, but the TOF method is particularly preferable because it can accurately measure the depth at a distance of several centimeters to several meters.

It is desirable that the shooting range of the 3D camera be as wide as possible in order to recognize an appropriate communication space. With a field angle of 80 degrees or more, which is equivalent to a wide-angle lens, a more realistic space can be perceived. Furthermore, it is desirable that the minimum resolution Δα in the angular direction is 0.033 degrees or less, which corresponds to a visual acuity of 0.5.

If the resolution of the stereoscopic camera is high definition (1080 x 1920 pixels), the angle of view must be 73 degrees or less to make Δα 0.033 degrees or less. degree or less. Therefore, when shooting at an angle of view of 80 degrees or more, it is desirable to shoot with a camera having a resolution of 4K or higher.

In FIG. 1, a digital communication network used for connecting to an external device for exchanging three-dimensional information requires transfer of moving images of three-dimensional information. A communication speed of 25 Mbps or higher is desirable for stable transfer of 4K images and video footage with depth information, and when using a mobile communication network, using a 5G or higher standard makes it easy to exchange information with remote locations. become.

Next, from the three-dimensional information transferred from the stereoscopic camera, the direction and intensity of light rays to be reproduced are calculated for each element cell by an arithmetic function. Furthermore, by controlling display functions such as LCD, OLED, and DMD, light source functions such as lasers, LEDs, and EL, and light control functions such as lens LCDs and diffractive optical elements, it is possible to control the direction of light rays for each element cell. By reproducing the intensity and intensity, it is possible to display a natural sense of distance and no blur. If the light source function and the light control function are passive and do not require control, they do not need to be controlled by the control function. A device that displays a three-dimensional image by controlling light in the direction and intensity calculated by the arithmetic function in this way is called a three-dimensional image display.
Note that when displaying three-dimensional information obtained from the outside via a communication function without using three-dimensional information obtained from a stereoscopic camera, the stereoscopic camera is not required in the system. Conversely, if only three-dimensional information from the stereoscopic camera is used, this system does not require a communication function.

Examples of the display function are generally two-dimensional display devices such as LCD, LED, OLED, and DLP, but a method of scanning a laser light source, an LED light source, or the like may also be used. Self-luminous devices such as LEDs and OLEDs have both a light source function and a display function. If the direction of light is controlled by a diffraction pattern such as a hologram, the display function and the light control function can be combined into one device. can be combined with The display surface means the surface on which the pattern is displayed by these display devices, and in the case of using a plurality of display devices, the surface closest to the observer.

FIG. 2 is a conceptual diagram and a plan view showing a usage example of the first embodiment of the three-dimensional image display system of the present invention. Although the display and the stereoscopic camera overlap in the figure, they are located at different positions in the Z direction and do not overlap. The position and direction of the stereoscopic camera may be any desired position and direction to view the image, and the number of stereoscopic cameras is not limited to one, and may be plural.

In the usage example of FIG. 2, the three-dimensional image display system is a three-dimensional image display communicator that achieves communication with a time difference between recording and reproducing three-dimensional information. That is, after the three-dimensional information of the real space captured by the stereoscopic camera is temporarily stored in the storage function, the three-dimensional image is reproduced in the reproduction space by the display at any time desired by the observer. As a result, even if the observer is not present at the time of photographing, the three-dimensional information of the real space to be observed can be known.
This example shows an example in which recording and playback are performed with a time lag. makes it possible to experience remote spaces without moving.

The example of use in FIG. 22 is a block diagram showing the configuration of a 3D image display that uses 3D information created without using a stereoscopic camera, such as a virtual character, or 3D information sent from an external system. It is a diagram. FIG. 22 shows an example in which a communication function is described for the purpose of inputting control information and information about a display image from the outside. is not limited to that.
FIG. 23 is a conceptual diagram and a plan view showing a usage example of the embodiment of the three-dimensional image display of the present invention. In FIG. 23, for example, a three-dimensional image generated by the configuration shown in FIG. 22 can be displayed on the display as a reproduced image.
In this way, by using the three-dimensional image display of the present invention, it is possible to interact more naturally with a non-existing partner such as a person or character created in a virtual space or with a partner sent from another system in an appropriate communication space. communication can be taken.

FIG. 3 is a block diagram showing the configuration of a three-dimensional image display system 20 according to the second embodiment of the invention. In FIG. 3, two or more block diagrams showing the configuration of the first embodiment 10 of the three-dimensional image display system of the present invention shown in FIG. It constitutes a 3D image display communicator that realizes natural communication between two or more remote locations. The three-dimensional information obtained by the stereoscopic camera is compressed/converted by an arithmetic function as necessary, and transmitted via a communication function.
Although there are no particular restrictions on the communication means for realizing this communication function, since three-dimensional information is handled, it is desirable to have a communication means capable of transmitting large amounts of information at high speed, such as the digital transmission network mentioned above. preferable.

FIG. 4 is a conceptual diagram and a plan view showing a usage example of the three-dimensional image display system according to the second embodiment of the present invention. The position, direction, and number of stereoscopic cameras may be the same as in FIG. In this usage example, the three-dimensional image display system of the present invention is a three-dimensional image display communicator that realizes natural communication between two remote locations connected by a digital transmission network.

That is, three-dimensional information of a remote member (one person in this example) photographed by a stereoscopic camera B in the physical space B is transferred from the communication function circuit B to the communication function circuit A. and the digital transmission network, and reproduced in the reproduction space A through the display A.
Similarly, for a member (one person in this example) existing in the physical space B, three-dimensional information of the physical space A of the remote member photographed by the stereoscopic camera A is transmitted from the communication function circuit A to the communication function circuit B. It is transmitted via a digital transmission network and reproduced in a reproduction space B via a display B.

In this case, the digital transmission network used for transmission also needs to be able to transmit moving images of 3D information. A communication speed of 25 Mbps or higher is desirable for stable transmission of moving images of 4K images and depth information. When using a mobile communication network, use a standard of 5G or higher, and easily communicate with remote locations. becomes possible.

In the three-dimensional image display system and the three-dimensional image display display of the present invention, large-sized element cells that are less affected by diffraction are used, and the pitch of the element cells is made smaller than the size of the element cells, so that a plurality of light rays are present in the pupil. , a three-dimensional image display system capable of focus adjustment can be realized. Therefore, the conditions of "element cell size" and "element cell pitch" necessary to reproduce an appropriate communication space will be explained.

Generally, a person with a visual acuity of 1.0 has an angular resolution of 1/60 degrees with the naked eye. Assuming that the wavelength is 500 nm, the size of the element cell at which the divergence angle θ due to diffraction is equivalent to this is given by (Equation 1) shown in [Background Art].
d=1.22×500×10 ⁻⁶ /tan (1/60°)×2
= 4.2 mm.
Similarly, the size of an element cell that produces a blur with an angular resolution of 1/60/0.7 degrees, which is equivalent to that of a person with visual acuity of 0.7, which is a requirement for a driver's license, is 2.9 mm.
Also, as described above, according to the research by Miyazaki et al., it can be regarded as a person with a visual acuity of 0.5 or more, who can communicate by looking at facial expressions at a distance of 3.6 m. By the same calculation, the size of the element cell that produces blur equivalent to the resolution of this visual acuity of 0.5 is 2.1 mm.

Therefore, the size of the element cell (d in FIG. 19; the above 4.2, 2.9, 2.1, . . . mm) is used as a parameter, and the distance from the display (L in FIG. Fig. 5 shows the calculation of the length of the blur due to diffraction as the axis.
As can be seen from FIG. 5, if the distance (L) from the display is the same, the larger the size (d) of the element cell, the shorter the length of the blur. This reflects the fact that the spread angle θ decreases as d increases in (Equation 1).

The size of the human pupil is generally 2 to 8 mm, and in order to allow a plurality of light rays to pass through the pupil and achieve focus adjustment of the eye, the interval (pitch) between the element cells must be at least 2 mm within the pupil. The pitch must be such that one or more element cells can be accommodated. In order to achieve more natural focusing, it is desirable that the number of light rays (the number of element cells) entering the pupil is large. In other words, it is desirable to reduce the interval (pitch) between element cells in order to increase the number of element cells.

Next, let us consider the required element cell pitch. FIG. 6 is a characteristic diagram obtained by calculating the resolution on the retina when an object is viewed, using the pitch at which the element cells are arranged as a parameter and the distance from the display as the horizontal axis. Since the distance between photoreceptors on the human retina is about 10 μm (0.01 mm), in order to have better resolution (smaller circle of confusion diameter), objects farther than 0.45 m should be 0 It can be seen that if the object is 0.2 mm or less and the distance is greater than 1.2 m, the element cell pitch of about 0.4 mm or less is required.

In addition, at a distance of 0.5 m, the resolution of a 24-inch XGA (Extended Graphics Array: a standard announced by IBM in 1990) display (circle of confusion diameter of about 30 μm (0.03 mm) on the retina). It can be seen that for acceptable applications, an elemental cell pitch of 0.5 mm or less for objects farther than 0.45 m and 1.2 mm or less for objects farther than 1.2 m will suffice.

Summarizing the above, in order to reproduce an appropriate communication space (distance range of 0.45 to 3.6m from the display), the element cell size is generally required to have a resolution equivalent to or higher than visual acuity of 0.5 at a distance of 3.6m. If the pitch of the element cells is 2.1 mm or more, and the pitch of the element cells is 0.5 mm or less, practically satisfactory communication becomes possible. If the element cell size is 4.2 mm or more and the pitch of the element cells is 0.2 mm or less, the object can be observed with the same resolution as the real object.

In addition, if communication is conducted at a social distance (range of 1.2 to 3.6 m from the display) or more, the element cell size should be 2.1 mm or more and the element cell pitch should be 1.2 mm or less. Enables trouble-free communication.
Further, when the element cell size is 4.2 mm or more and the element cell pitch is 0.4 mm or less, it is possible to observe the object with a resolution equivalent to that of the actual object. At this time, assuming that the element cell size is d and the element cell pitch is p, the relationships d≧2.1 mm and d/p≧1.75 are satisfied.

The minimum resolution Δα in the angular direction of the reproduced light beam is meaningless even if it is smaller than twice the divergence angle θ due to diffraction (Δα≧2×θ). Since the magnitude of Δα also causes blurring, in order to obtain a blur equivalent to a visual acuity of 1.0, Δα is about 1/60=0.017 degrees when the visual acuity is 1.0, and the visual acuity is 0.5. Δα in equivalent is about 1/60/0.5=0.033 degrees. From the above, it is desirable that Δα is at least 0.04 degrees or less in order to reproduce a space with depth. If it is 0.017 degrees or less, a blur equivalent to that obtained when a person with normal vision sees a real object can be obtained.
Of course, the permissible range of bokeh differs depending on the application. For example, if the range of visual acuity is from 0.3 to 1.5, the range of Δα is (1/60/1.5=0.01 degrees)<Δα<(1/60/0.3=0.05 degrees).

As described above, in any combination (the appropriate communication space or a social distance space that is a part thereof, and the general visual range), in order to realize the object reproduction in the appropriate communication space, which is the purpose of this application, , the pitch between the element cells is narrower than the size of the element cells, and when the element cells are arranged, adjacent element cells need to overlap each other.

However, if the degree of overlap of the element cells is high, disadvantages such as complication of the mechanism, increase in calculation time, and increase in fabrication time occur, so it is not desirable to overlap the element cells more than necessary.
If d is the element cell size and p is the pitch between the element cells, the demerits due to multiplexing can be suppressed if d/p<25, and at least d/p<100 is sufficient. However, this does not apply if the demerits of increasing the overlap of the element cells become practically unproblematic due to advances in technology or the like.

Various methods are conceivable for superimposing adjacent element cells. A holographic stereogram is a type of light field display that uses hologram technology to reproduce the direction of light rays, and generally reproduces only the direction of light rays and not the wavefront from an object. Element cells using holograms are hereinafter appropriately referred to as "element holograms".

For example, in Japanese Patent Application Laid-Open No. 2013-195802 and Japanese Patent No. 3948199, element holograms recording the directions of light beams are sequentially created. Japanese Patent Application Laid-Open No. 2013-195802 is for exposing and forming interference fringes by laser light on a photosensitive material, and when the element hologram is a hologram based on unevenness on the surface, mass production is easy and inexpensive. . Japanese Patent No. 3948199 describes a case where an interference fringe pattern calculated by a computer is recorded by an electron beam lithography device or the like and reproduced in real time by an acousto-optic device or a liquid crystal panel. When an element hologram is constructed by , it becomes possible to reproduce it in real time.

However, in these examples, the size and pitch of the element holograms are not optimized, and the object to be reproduced is limited to the vicinity of the hologram or the vicinity of the imaging position of the parallax original image (the reproduction position of the master hologram), and the depth is wide. It does not show how to reproduce a certain space.

Since the elemental holograms of a holographic stereogram are usually composed of interference fringes indicated by the intensity of light, it is possible to record them in an overlapping manner, and it is possible to make the size of the elemental holograms larger than the pitch of the elemental holograms. be.

When recording with overlapping light intensities, if the hologram is thin and the degree of multiplicity is high, the diffraction efficiency of each elemental hologram may decrease, resulting in a dark reproduced image with a lot of noise. If the interference fringes are recorded on a device having a thickness of 1 μm to several tens of μm as a recording material, a bright reproduced image with little noise can be obtained even if the multiplicity is high.

FIG. 7 is a schematic diagram when the element cell (element hologram) pitch p is smaller than the element cell (element hologram) size d, and is a configuration diagram of the hologram viewed from the front. In this figure, element cells A, B, C, and D are laid out with overlapping portions.

FIG. 8 is a schematic diagram when the element cell pitch is smaller than the element cell size (p<d) according to the embodiment of the three-dimensional image display of the present invention, and is an explanatory view of the hologram viewed from the side. . It shows a mode in which the reproduced light beams of the element cells are emitted from the display surface (hologram surface) while overlapping each other. Light rays exiting the display surface are resolved at an angle of Δα.

Next, the relationship between the element cell size and the pitch will be described more specifically, taking as an example the case where the element cells are formed of diffraction gratings. FIG. 9 is a configuration diagram illustrating a conventional element cell for comparison. The relationship between element cell size d and pitch p is p≧d. The patterns are also independent without overlapping.

FIG. 10 is a configuration diagram illustrating an element cell having a relationship that the element cell pitch is smaller than the element cell size (p<d) according to the embodiment of the three-dimensional image display of the present invention. When p<d, the overlapping portion of the element cells is the sum of their respective diffraction grating patterns. The example of FIG. 10 shows an example in which a pattern is configured with fine pixels of 1/10 or less of the diffraction grating pitch for the diffraction gratings that form the element cells.

When an element cell composed of a diffraction grating is used in a coarse display device, a resolution of half or less than the pitch of the finest diffraction grating is sufficient to represent the diffraction grating.
FIG. 11 relates to the embodiment of the three-dimensional image display of the present invention, and shows another example of an element cell having such a relationship that the element cell pitch is smaller than the element cell size (p<d), and is composed of a diffraction grating. This is an example of using element cells for a rough display device.

In the above, an example of using a holographic stereogram as a method of making the pitch between element cells smaller than the size of the element cells was shown. In a light field display, the display image is changed in synchronization with the vibrating positional information by vibrating the display at high speed. It becomes possible to make the pitch smaller than the element cell size. Further, when reproducing a holographic stereogram using an electronic hologram, the reproduction may be performed while slightly changing the positions of the element holograms. In any case, by setting the size of the element cells and the pitch between the element cells to optimum values, it is possible to observe a natural stereoscopic image without blurring in an appropriate communication space.

FIG. 12 is a conceptual diagram when a point object is reproduced as an object point A' by a holographic stereogram in which element cells whose pitch is smaller than the size of the element cells are arranged on the display surface. Each element cell reproduces the direction of light emitted from the object point A on the display surface. Observing from various directions above the drawing, the observer can see as if the object point A exists from each direction.

Also, the pitch of the element cells is sufficiently small relative to the size of the pupil (see the description of FIG. 6 above), and the size of the element cells is set to a size that causes little blurring due to diffraction (see the description of FIG. 5 above). For the observer, conditions necessary for stereoscopic vision such as convergence, focus adjustment, and binocular parallax are reproduced without contradiction, so it is possible to reproduce a space away from the display surface naturally without feeling tired.

As shown in FIG. 12, a light ray emitted from each element cell has a width equal to the size (d) of the element cell+spreading due to diffraction (Δα in FIG. 8). Therefore, there is no problem when observing a space far from the display surface, but when observing an object close to the display surface, the resolution of the object decreases.

There are several possible ways to solve the above problem. For example, the brightness distribution of light rays reproduced from the element cells is bright at the center and dark at the periphery, as shown in FIG. By doing so, it is possible to improve the resolution of the reproduced object. Such a light beam brightness distribution can be achieved by varying the diffraction efficiency within the element cells so that the transmittance of the interference fringe pattern recorded in the element cells decreases toward the periphery.

As another method, the following method is conceivable. As an element cell, an element cell is formed on the display surface in which the interference fringes of the spherical wave diverging from the object point A and the reference light are recorded. By doing so, as shown in FIG. 14, it is possible to reduce the size of the object point A'' by the light beam reproduced from each element cell to the diffraction limit of the element cell size.

A mode in which a plurality of objects are reproduced by the method of FIG. 14 will be described with reference to FIG. Interference fringes between the spherical wave diverging from each point on the object and the reference light are recorded in each element cell on the display surface. A near object B' produces a spherical wave diverging from a nearby light point, and a distant object C' produces a spherical wave diverging from a distant light point. Thus, the wavefront is recorded differently depending on the distance from the object.

The interference fringes of the spherical wave diverging from each point on the object and the reference light are digitized through a stereoscopic camera in the same way as in a normal digital hologram. , points resolved at an angle of Δα from each element cell position, the method of the embodiment of the present invention, in contrast to the need to calculate the wavefront at a sampling pitch of μm order in a normal digital hologram Then, sampling should be performed at a pitch of several millimeters to several centimeters, and a huge amount of calculation can be avoided. In addition, since the sampling pitch increases as the distance from the display surface increases, this method is suitable for reproducing a wide space away from the display surface.

Since the holographic stereogram is created so as to reproduce the directions of light rays, it is possible to create three-dimensional image display data from images of an object photographed from a plurality of directions. For this reason, by using CG (computer graphics) techniques, which are being studied in various ways, it is possible to reproduce glossy objects and transparent objects, and by photographing actual objects, it is possible to reproduce real objects. Playback is also possible.

For example, a method of calculating a hologram pattern by applying a ray tracing method, which is one of CG techniques, will be described with reference to FIG.
First, the center of each element cell becomes the starting point of a ray emitted by the ray tracing method. Next, the ray tracing method is performed with the center of each element cell as the starting point, and the intersection point between the ray and the object to be photographed is obtained. As a result, each element cell has a set of point light sources from different viewpoint positions, making it possible to create a pattern of element cells with vertical and horizontal parallax.
The object (subject) here may be obtained from information captured by a stereoscopic camera, or may be a virtual object created by CAD or the like.
In this calculation, when only the direction of the ray is taken into consideration, the reproduction by the ray is as shown in FIG. It becomes reproduction by a bright ray.

FIG. 24 shows an example of a flow chart for calculation of a hologram pattern in consideration of the direction of light and the distance to an object point.
First, three-dimensional information of an object to be displayed is input. Next, the position of the center of the element cell to be calculated is determined, and the points of intersection between the object and each line diverging from the center position of the element cell and having different angles by Δα are determined. The point of intersection with each object is defined as an object point, and the sum of the complex amplitudes at the element cell positions of the spherical waves diverging from each object point is obtained. The complex amplitude to be obtained may be within the size range of the element cells.
The above steps are performed for all element cells, and then the complex amplitude on the display surface is obtained by obtaining the sum of the complex amplitudes of all element cells. Next, by obtaining the pattern of interference fringes between the wavefront of the reference light and the complex amplitude on the display surface, it is possible to obtain the pattern to be expressed on the display.
In this way, instead of taking the sum of the interference fringe patterns for each element cell, the sum of the complex amplitudes is obtained, and then the calculation to obtain the interference fringe pattern with the reference beam is performed. It is possible to record and reproduce a three-dimensional image of an object including the distance of .

In the above, in order to suppress the decrease in efficiency (brightness) due to multiplexing due to the pitch being smaller than the size of the element cells, after calculating the sum of the complex amplitudes of the element cells, the interference pattern with the reference light is calculated, the sum of the interference patterns may be obtained after obtaining the interference pattern with the reference light for each element cell. In that case, since calculation can be performed for each element cell, parallel calculation is facilitated and calculation time is shortened.

The stereogram (three-dimensional information of an object) to be recorded may be a stereogram with only horizontal parallax. is desirable. Also, although an example of a circular cell is shown as an element cell, it is not necessary to be limited to a circular one, and polygons such as triangles, quadrilaterals, pentagons, and hexagons, stars, ellipses, rectangles, and the like may be used.

As the light source for reproducing the created holographic stereogram, it is desirable to use a monochromatic light source such as a laser or LED, or a light source that combines a normal light source and a filter, in order to eliminate blurring due to differences in diffraction angles due to wavelengths. In the case of using a laser light source, it is desirable to take measures to reduce coherence in order to reduce noise due to speckles.

The coherence of a laser can be reduced by passing it through an optical fiber, vibrating the light source, changing the optical path length, inserting a moving diffusing element into the optical path, or combining multiple light sources.

So far, the appropriate communication distance has been set from 0.45 m to 3.6 m. All you have to do is Also, the object (object) to be reproduced is not limited to a person, and may be an animal, a robot, or the like, or may be a two-dimensional image reproduced in space. Furthermore, it may be one that reproduces a desk, a chair, a table, etc. in a space that suggests the existence of a communication target. Furthermore, even if the target does not directly take communication, the main target of remote control, such as heavy equipment, remote surgery, outer space, military, etc., may be in the form of being within an appropriate communication distance.

Furthermore, the appropriate communication distance has been set at 0.45m to 3.6m, but from the research results of Miyazaki et al. Therefore, the optimum communication distance may be changed from 0.45m to 7.0m.

The element cell size and element cell pitch conditions defined in the present invention correct the magnification of the optical system when the display is observed through an optical system such as an eyepiece.
For example, if the element cell size d is 2.1 mm and the element cell pitch p is 0.5 mm in the proper communication distance of 0.45 m to 3.6 m without an eyepiece, the present invention can be applied to a head-mounted display or the like. When the embodiment is applied and the magnification of the eyepiece lens is 2, the element cell size d is 2.1/2=1.05 mm, and the element cell pitch p is 0.5/
2=0.25 mm. At this time, the multiplicity of element cells remains unchanged at d/p=4.2.
Conversely, when the reduction optical system is used and the magnification of the optical system is 0.5, the element cell size d is 2.1/0.5=4.2 mm, and the element cell pitch p is 0.5/ 0.5=1.0 mm. In this case as well, the multiplicity of element cells remains unchanged at d/p=4.2.

According to the first embodiment of the three-dimensional image display system of the present invention, for example, in the fields of childcare, medical care, and nursing care, the state of infants, patients, and care recipients when their parents are unavoidably absent can be displayed later. It can be used for observation, etc.
In addition, according to the second embodiment, it can be used to communicate more closely and intimately with others in business or private settings.

10: Three-dimensional image display system according to the first embodiment of the present invention 20: Three-dimensional image display system according to the second embodiment of the present invention

Claims (20)

A three-dimensional image display system comprising at least a stereoscopic camera and a three-dimensional image display,
The stereoscopic camera has a function of acquiring information on the incident direction and intensity of light rays incident on the imaging surface from the object to be photographed,
The three-dimensional image display has at least an arithmetic function, a display function, and a light control function, and comprises a plurality of arranged element cells,
the arithmetic function has a function of calculating the direction and intensity of light rays to be reproduced for each of the plurality of element cells after receiving the information from the stereoscopic camera;
the plurality of elemental cells displaying a three-dimensional image of the object by reproducing the calculated ray directions and intensities;
the size of the plurality of element cells is larger than the pitch at which the plurality of element cells are arranged;
When the size of the plurality of element cells is d, d is 2.1 mm or more, and when the pitch at which the plurality of element cells are arranged is p, p is 1.2 mm or less,
In the element cells, interference fringes of spherical waves diverging from intersections of a plurality of light rays in different directions starting from the centers of the element cells and the object and the reference light are recorded.
A three-dimensional image display system characterized by: a storage function for storing the result of calculation by the calculation function;
2. The three-dimensional image display system according to claim 1, further comprising either or both of a communication function capable of communicating with the outside of the system wirelessly or by wire. The minimum angular resolution of the rays reproduced from the plurality of element cells is 0.033 degrees or less.
3. The three-dimensional image display system according to claim 1 or 2, characterized by: When the three-dimensional image display constitutes a head-mounted display including an eyepiece, and the magnification of the eyepiece is r,
A size d of the plurality of element cells is 2.1/r mm or more, and a pitch p at which the plurality of element cells are arranged is 1.2/r mm or less.
The three-dimensional image display system according to any one of claims 1 to 3 , characterized by: A size d of the plurality of element cells is 2.1 mm or more, and a pitch p of arranging the plurality of element cells is 0.5 mm or less.
The three-dimensional image display system according to any one of claims 1 to 4 , characterized in that: When the three-dimensional image display constitutes a head-mounted display including an eyepiece, and the magnification of the eyepiece is r,
A size d of the plurality of element cells is 2.1/r mm or more, and a pitch p at which the plurality of element cells are arranged is 0.5/r mm or less.
The three-dimensional image display system according to any one of claims 1 to 5 , characterized in that: For the three-dimensional image, the arithmetic function obtains intersections between a plurality of light rays in different directions starting from the center of each element cell and the object, and calculates the sum of complex amplitudes of wavefronts from each intersection, For the calculated sum data, calculate the interference fringes with the reference light, display the interference fringes on the display function, and display by illuminating the illumination light,
The three-dimensional image display system according to any one of claims 1 to 6 , characterized by: A method of using the three-dimensional image display system according to any one of claims 1 to 7 ,
The distance from the display surface of the three-dimensional image display to a part of the three-dimensional image of the object is 0.45 to 7 m.
A method of using a three-dimensional image display system characterized by: A method of using the three-dimensional image display system according to any one of claims 1 to 7 ,
The distance from the display surface of the three-dimensional image display to a part of the three-dimensional image of the object is 1.2 to 7 m.
A method of using a three-dimensional image display system characterized by: The reproduced light beam is stored in a memory function, and later, the observer observes the three-dimensional image by reproducing the memory using the three-dimensional image display,
A method of using the three-dimensional image display system according to claim 8 or 9 . Two or more systems of the three-dimensional image display system according to any one of claims 1 to 7 are installed at two or more locations separated from each other, and the two or more systems are connected by a digital transmission network via a communication function, and the three characterized by transmitting a dimensional image,
A method of using the three-dimensional image display system according to any one of claims 8 to 10 . A three-dimensional image display, comprising a collection of a plurality of element cells, where d is the size of the plurality of element cells, d is 2.1 mm or more, and p is the pitch at which the plurality of element cells are arranged. When p is 1.2 mm or less,
In the element cells, interference fringes of the reference light and spherical waves diverging from intersections of a plurality of light rays in different directions starting from the center of each element cell and an object to be photographed are recorded.
A three-dimensional image display, characterized by: When the three-dimensional image display constitutes a head-mounted display including an eyepiece, and the magnification of the eyepiece is r,
A size d of the plurality of element cells is 2.1/r mm or more, and a pitch p at which the plurality of element cells are arranged is 1.2/r mm or less.
13. The three-dimensional image display display according to claim 12 , characterized by: A size d of the plurality of element cells is 2.1 mm or more, and a pitch p of arranging the plurality of element cells is 0.5 mm or less.
14. The three-dimensional image display display according to claim 12 or 13 , characterized by: When the three-dimensional image display constitutes a head-mounted display including an eyepiece, and the magnification of the eyepiece is r,
A size d of the plurality of element cells is 2.1/r mm or more, and a pitch p at which the plurality of element cells are arranged is 0.5/r mm or less.
14. The three-dimensional image display display according to claim 12 or 13 , characterized by: The three-dimensional image display has at least an arithmetic function,
In the arithmetic function, intersections between a plurality of light rays in different directions starting from the center of each element cell and the object are obtained, the sum of complex amplitudes of wavefronts from each intersection is calculated, and the calculated sum is calculated. calculating interference fringes with reference light for the data, displaying the interference fringes on a display function, and displaying a three-dimensional image of the object by illuminating with illumination light;
The three-dimensional image display display according to any one of claims 12 to 15 , characterized by: The method of using the three-dimensional image display according to any one of claims 12 to 16 , wherein the distance from the display surface of the three-dimensional image display to a part of the three-dimensional image of the object is 0.45. 7 m. The method of using the three-dimensional image display according to any one of claims 12 to 16 , wherein the distance from the display surface of the three-dimensional image display to the part of the three-dimensional image of the object is 1.2 7 m. 19. The method of using a three-dimensional image display according to claim 17 or 18 , wherein at least one of the three-dimensional images of objects is a person. A method of using the three-dimensional image display according to any one of claims 16 to 18 ,
The reproduced light beam is stored in a memory function, and later, the observer observes the three-dimensional image by reproducing the memory using the three-dimensional image display.
A method of using a three-dimensional image display, characterized by: