JP2001320738A - Three-dimensional display method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional display method capable of improve an image by removing an excessive image generated falsely in an image to be displayed. SOLUTION: When the display object body is with the three-dimensional object which should be displayed, and the background object, a first two-dimensional image projecting the three-dimensional object to be displayed on at least two screens from the observer's sight direction is displayed on at least the two screens of a plurality of screens. A second two-dimensional image consisting of the portions, which do not lap with the three-dimensional object to be displayed, of the two-dimensional image which projected the background object on the back screen from the observer's line of sight direction, and an embedded image displayed at least in a region adjacent to the second two-dimensional image among the display areas of the two-dimensional image which projected the three-dimensional object to be displayed on the back screen from the observer's line of sight direction are displayed on the back screen located behind at least the above two screens when viewed from the observer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional display method, and more particularly, to a method of displaying a two-dimensional image on a plurality of display surfaces at different depth positions as viewed from an observer by independently changing the luminance. In addition, the present invention relates to a technique effective when displaying a three-dimensional stereoscopic image.

[0002]

2. Description of the Related Art A two-dimensional image is displayed on a plurality of display surfaces at different depth positions as viewed from an observer, and the brightness of the two-dimensional image displayed on each display surface is independently changed. A three-dimensional display method capable of continuously displaying a three-dimensional stereoscopic image is disclosed in, for example, Japanese Patent No. 3022558. The three-dimensional display method described in this publication is
As shown in FIG. 5, optically, a plurality of display surfaces, for example,
The three display surfaces (201 to 203) are arranged at different depth positions when viewed from the observer 100. For example, display surface 2
When displaying a three-dimensional stereoscopic image of the three-dimensional object 207 existing between the display surface 201 and the display surface 202, the two-dimensional image projected on the display surface (201, 202) when the three-dimensional object 207 is viewed from the observer 100. (204, 205), and these two-dimensional images (204, 205) are displayed on the display surface (201, 20).
2) and their two-dimensional images (204, 204)
205) is changed according to the depth position of the three-dimensional object 207. By doing this,
The two-dimensional images (204, 205) are displayed on the display surface (201, 20).
Despite being displayed only at the depth position of 2), the observer 100 can be made to feel that it is at the depth position of the three-dimensional object 207.

[0003]

However, in the above-described method, in addition to the three-dimensional object 207 to be displayed,
If there is a background object 208 that at least partially overlaps the three-dimensional object 207 as viewed from the observer 100 and that is to be displayed behind, there is a problem if this method is simply applied. That is, as shown in FIG. 5, the two-dimensional image 209 displayed on the display surface 203 is a three-dimensional object 207 based on the two-dimensional image projected on the depth position of the display surface 203 when the background object 208 is viewed from the observer 100. Two-dimensional image 206 projected on the depth position of display surface 203 as viewed from observer 100
It is necessary to form a two-dimensional image in which the display area is cut out.
This is because, if the projected two-dimensional image of the background object 208 is displayed as it is in this part, the projected two-dimensional image and the previous two-dimensional image (204, 205) are optically overlapped, which is different from the image to be displayed. This is because it becomes an image. As described above, on the display surface 203, the display area of the two-dimensional image 206 is cut out adjacent to (or in the form of, or inside of) the two-dimensional image 209 displayed on the display surface 203. Is displayed.

However, when the display area of the projected two-dimensional image 206 is cut out and displayed, the difference between the right and left positions of the right eye and the left eye of the person causes a difference as shown in FIG.
From one eye, the cut-out two-dimensional image 206 can be seen, and this generates a pseudo-unnecessary and unnatural two-dimensional image around the three-dimensional object 207. In particular, when the two-dimensional image 206 is seen by the observer 100 as a color similar to black, an extra two-dimensional image is generated as a shadow. This is a problem that is difficult to solve optically because the right eye and the left eye see from different positions. The present invention has been made in order to solve the problems of the conventional technique, and an object of the present invention is to remove an unnecessary image that is generated in a displayed image in a pseudo manner, thereby improving the image. It is to provide a three-dimensional display method. The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0005]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows. That is, the present invention generates a two-dimensional image by projecting a display target object from a line of sight of the observer on a plurality of display surfaces at different depth positions as viewed from the observer. Displaying a three-dimensional image on each of a plurality of display surfaces at different depth positions as viewed from the observer, and independently changing the brightness of the displayed two-dimensional image for each of the display surfaces, A three-dimensional display method of generating an image, wherein the display target object is located behind the three-dimensional object to be displayed and the three-dimensional object to be displayed as viewed from the observer, and a part of the display object is displayed. In the case where the background object overlaps with the three-dimensional object to be displayed, the at least two of the three-dimensional objects to be displayed are displayed on at least two of the plurality of display surfaces from the viewing direction of the observer. First secondary projected on display surface A two-dimensional image in which an image is displayed and the background object is projected from the observer's line of sight to the rear display surface on a rear display surface located behind the at least two display surfaces as viewed from the observer. of,
A second two-dimensional image consisting of a portion that does not overlap with the three-dimensional object to be displayed, and a display area of a two-dimensional image in which the three-dimensional object to be displayed is projected onto the rear display surface from the line of sight of the observer. And at least an embedded image displayed in an area adjacent to the second two-dimensional image.

In a preferred embodiment of the present invention, the embedded image is an image other than colorless and transparent, an image other than black,
Alternatively, it is an image other than white. In a preferred embodiment of the present invention, the embedded image is a two-dimensional image obtained by projecting a portion of the background object overlapping with the three-dimensional object to be displayed from the observer's line of sight to the rear display surface, or A two-dimensional image in which a portion of the background object overlapping the three-dimensional object to be displayed is projected from the direction of the observer's line of sight to the rear display surface, and an image similar in color, luminance, or transmittance. In a preferred embodiment of the present invention, the embedded image is an image of an area of the second two-dimensional image adjacent to the embedded image, or an image of an area of the second two-dimensional image adjacent to the embedded image. The images have similar images, colors, brightness, or transmittance.

In a preferred embodiment of the present invention, the embedded image is a two-dimensional image obtained by projecting a portion of the background object overlapping with the three-dimensional object to be displayed from the direction of the observer's line of sight to the rear display surface; Alternatively, it is a combination of the embedded image of the second two-dimensional image and an image of a region adjacent to the embedded image, or an image that has been subjected to image processing. In a preferred embodiment of the present invention, the image processed image is a two-dimensional image projected on the rear display surface from the direction of the observer's line of sight, where the background object overlaps the three-dimensional object to be displayed, or , An image of an area of the second two-dimensional image adjacent to the embedded image is averaged, blurred, deformed, repeated, or transformed.

In a preferred embodiment of the present invention, the embedded image is obtained by parallax between a right eye and a left eye of the observer.
The first two-dimensional image and the three-dimensional object to be displayed are displayed in an area where the two-dimensional image projected on the rear display surface from the line of sight of the observer is not completely overlapped and is shifted. In a preferred embodiment of the present invention, the embedded image has an image whose luminance is gradually decreased or whose luminance is gradually increased from a boundary with the second two-dimensional image toward the center of the display area. It is an image.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments, components having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted. In this embodiment, the expression “surface” on which an image is arranged is used, but this is the same expression as an image surface often used in optics and the like, and as a means for realizing such an image surface. Is
For example, various optical elements such as a lens, a total reflection mirror, a partial reflection mirror, a curved mirror, a prism, a polarizing element, and a wave plate, and, for example, a CRT (cathode ray tube) display, a liquid crystal display, an LED (Light Emission Diode) display, Plasma display, FED (Field Emissio)
n Display, DMD (Digital Mirro)
It is obvious that the present invention can be realized by many optical combination techniques using a two-dimensional display device such as an (r Display) display, a projection display, and a line drawing display.

[First Embodiment] FIG. 1 is a diagram for explaining the principle of a three-dimensional display method according to the present embodiment. In the present invention, as shown in FIG. 1, a plurality of surfaces are provided on the front surface of the observer 100, for example, at different depth positions when viewed from the observer.
An optical system is constructed using a two-dimensional display device and various optical elements in order to set a plurality of display surfaces (1011 to 101n) and display a plurality of two-dimensional images on these surfaces (1011 to 101n). . Examples of the two-dimensional display device include a CRT display device, a liquid crystal display, an LED display, a plasma display, an FED display,
For example, a lens, a total reflection mirror, a partial reflection mirror, a curved mirror, a prism, a polarizing element, a wave plate, or the like is used as an optical element. For the setting method of the display surface, refer to the above-mentioned publication (Japanese Patent No. 3022558).

[0011] Further, these display surfaces are formed by a transmissive display device (for example, a twisted nematic liquid crystal display,
In-plane liquid crystal display, homogeneous liquid crystal display, ferroelectric liquid crystal display, guest-host liquid crystal display, polymer dispersed liquid crystal display, holographic polymer dispersed liquid crystal display,
Or a combination thereof) and various optical elements.

In this embodiment, three of the plurality of display screens will be mainly described. However, it is apparent that the same can be applied to other display screens. First, a method for displaying a continuous three-dimensional image is to display the three-dimensional object as viewed from the observer 100 on at least two display surfaces sandwiching the depth position of the three-dimensional object to be displayed by using these display surfaces (1011 to 101n). Is to display the two-dimensional images projected onto the three-dimensional object, and to change the luminance or transmittance of these two-dimensional images according to the depth position of the three-dimensional object. By doing so, the observer 100 can be made to feel that the two-dimensional image is at the depth position of the three-dimensional object, even though the two-dimensional image is only at the depth position of the display surface. In the conventional method, when a background object exists at least partially overlapped with the three-dimensional object as viewed from the observer 100 and a background object exists behind the three-dimensional object, there is a problem that a pseudo unnecessary image is generated around the three-dimensional object. Was optically difficult to resolve.

The present embodiment is an example for solving this problem, and in order to simplify the explanation, the three-dimensional object 103 to be displayed between the display surfaces (1011 and 1012) in FIGS. Yes, display surface (1012, 1013)
A description will be given of a case where there is a background object 104 to be displayed in between. However, the same applies to other cases. First, as shown in FIG. 2, the observer 10 is placed on a display surface (1011 and 1012) sandwiching the depth position of the three-dimensional object 103.
A two-dimensional image (10
21, 1022) and generate a two-dimensional image (102
1, 1022) on the display surface (1011, 101).
2) and the two-dimensional images (1021, 1
022) of the three-dimensional object 103
By changing according to the depth position of the 3D object 1
03 can be continuously expressed.

Next, two-dimensional images (105, 106) of the background object 104 projected from the observer 100 are generated on the display surface (1012, 1013), and these two-dimensional images (105, 106) are generated. Each display surface (1012, 10
13) and these two-dimensional images (105, 10).
6) The luminance (or transmittance) is changed according to the depth position of the background object 104. The present embodiment is different from the conventional method in that the three-dimensional object 103 adjacent to (or in the form of, or inside of) the two-dimensional image 106 displayed on the display surface 1013 is viewed by the observer 100. Two-dimensional image 10 projected to the depth position of display surface 1013
The portion adjacent to the two-dimensional image 106 in the display area 7 is filled with the following method as shown in FIG. That is, the three-dimensional object 1 viewed from the observer 100
A method of filling a part of the background object 104 behind the image 03 with a two-dimensional image projected on the display surface 1013 or using a part of the background object 104 adjacent to the two-dimensional image 107 is adopted.

When this part is filled in, as shown in FIG.
Optically, the projected two-dimensional image 107 is filled with an image similar to the two-dimensional image 106 in the two-dimensional image viewed from the left eye, so that the two-dimensional image can be seen without any discomfort. On the other hand, the two-dimensional image viewed from the right eye is the previous two-dimensional image (1021, 102
It is feared from an optical point of view that it causes another problem that it looks different from the three-dimensional object 103 because it appears to overlap with 2). However, when a person actually observes, in either case of filling, a sufficient effect can be obtained as long as the portion to be filled is near the boundary, and the observer 100 does not feel an extra image generated in a pseudo manner, Moreover, the observer 100 hardly feels the influence on the three-dimensional object 103. That is, it is a key point of the present embodiment that the problem can be solved visually, although the occurrence of the problem cannot be avoided optically.

This is considered to be due to the following reasons. Normally, people perceive depth by using both left and right eye images, but the texture, color,
In extreme cases, such as brightness and transparency, an image of only one eye is used, and information of the other eye is often discarded. However, as in the conventional method, even with one eye,
Texture, color, brightness, between 3D object and background object
When an image having extremely different transparency or the like (for example, the two-dimensional image 206 seen from the left eye shown in FIG. 6A) is inserted,
It is considered that a visual field conflict occurs between the two eyes without suppression for one eye, or a different image becomes dominant and suppresses the other, and this appears as a pseudo unnecessary image. In particular, in the case of an image such as a black image that is often experienced in the periphery of an object in the real world as a shadow or the like, this image tends to be dominant.

On the other hand, when the image is filled with the two-dimensional image 107 of the background object 104 as in the present embodiment, an image having almost no problem with at least one eye (for example, FIG.
(A two-dimensional image that can be seen from the left eye shown in (a)). The other eye overlaps the previous two-dimensional image and optically appears as a different image (for example, a two-dimensional image seen from the right eye shown in FIG. 3B), but does not extremely deviate from the accurate image. Therefore, there is no binocular rivalry between the two. Further, an image having no previous problem (for example, a two-dimensional image seen from the left eye shown in FIG. 3A) and this different image (for example, a two-dimensional image seen from the right eye shown in FIG. 3B) Compared with the above, since the image without the previous problem for the human is the image that is usually experienced, this image is adopted, and the different image is suppressed. For this reason, it is considered that the observer 100 does not feel any pseudo unnecessary images nor the above-mentioned different images overlapped with each other.

Therefore, to the extent that this idea does not emerge,
Obviously, there are many images and methods for filling the part of the two-dimensional image 107. For example, in an extreme case, when the background object 104 is thinner than the preceding three-dimensional object 103 and has little effect, not only the boundary region but also the whole may be filled. Alternatively, the image may simply be filled with an image other than colorless and transparent, an image other than black, or an image other than white. Thereby, the load on the image processing can be reduced.

The area that needs to be filled at least is the part where the projected two-dimensional image 107 in the two-dimensional image of the left eye shown in FIG. 3A is visible beside the two-dimensional image (1021, 1022). Fig. 6 of the conventional method
The two-dimensional image 206 in the two-dimensional image of the left eye shown in (a) indicates a part including a part seen beside the two-dimensional image (204, 205). Of course, this part also exists in the two-dimensional image viewed from the right eye, and it is necessary to fill in the present invention depending on the positional relationship between the background object to be displayed and the three-dimensional object to be displayed. In other words, it indicates a portion where the display of the three-dimensional object 103 to be displayed on the display surface 1012 and the display of the projection on the display surface 1013 are displaced without completely overlapping due to the parallax between the right eye and the left eye.

If there is no background object 104 in the vicinity, the object does not become a shadow and does not need to be particularly buried.
The two-dimensional image seen from the right eye of FIG.
If there is, it must be filled (for example, a two-dimensional image seen from the left eye in FIG. 3A). Of course, it is clear that there may be excess or deficiency in a part smaller than the human eyesight or in a range that is difficult to see psychologically. In particular,
It is clear that psychological increase / decrease can be used, such as setting a large value with a gradation, or setting the luminance slightly higher and setting it slightly shorter. Also, in the case of a complicated shape, it is obvious that the projected two-dimensional image side of the three-dimensional object 103 in a portion to be buried in a range unknown to a person can be formed in a simple shape.

Hereinafter, some examples of the filling method are shown in FIG. 4 in comparison with the conventional method. However, the image to be filled is shown as an image on the two-dimensional display image 1013 in FIG. 1 and, for the sake of simplicity, is shown with a different background image from FIG. FIG. 4A illustrates a portion of the background object 104 that is behind the three-dimensional object 103 and can be seen only from one eye of the observer 100 or from both eyes.
13 is an example of filling using a two-dimensional image projected on the image 13. Note that an image in which the portion of the background object 104 that can be seen only by one eye of the observer 100 or invisible by both eyes is embedded, hereinafter, referred to as an embedded image. FIG. 4B is a display area of a two-dimensional image in which the three-dimensional object 103 is projected on the display surface 1013, and is adjacent to a part of the two-dimensional image in which the background object 104 is projected on the display surface 1013. , Observer 1
This is an example of using a two-dimensional image of the background object 104 visible from both eyes at 00 to fill in this hollowed out shape.

The following is a description of the three-dimensional object 1 shown in FIG.
An example in which a part of the background object 104 which is behind the image object 03 and which can be seen only by one eye of the observer 100 or invisible by both eyes is used to perform image conversion will be described. ) Is projected onto the display surface 1013 and the background object 104 is projected on the display surface 1013.
It is apparent that the same result can be obtained by applying the image of the background object 104 visible from both eyes of the observer 100 adjacent to the hollowed-out portion of the two-dimensional image projected on 13. Further, even if the image processing is performed, the shape of the portion to be filled does not change significantly. Performing the following image processing may increase the processing, but has an advantage that an image that is accidentally included in the partial image and that is conspicuous due to sharpening can be eliminated, and the image can be embedded without discomfort. FIG. 4 (c)
Is an example of embedding using a two-dimensional image obtained by averaging the luminance and / or color components of the embedded image. This averaging may be either averaging only in the left-right direction, averaging only in the up-down direction, or averaging as a whole.

FIG. 4D shows an example in which the embedded image is filled with a blurred two-dimensional image. As a method of blurring, a method using a two-dimensional image shifted in the horizontal direction, the vertical direction, the oblique direction, etc., weighting the luminance or color component of the pixel or adding it to adjacent pixels using Gaussian distribution Obviously, there are various methods such as a moving method. FIG. 4E shows an example in which a part of the embedded image is filled using a repeated two-dimensional image. This has an advantage that the image processing is light because only a part of the image is used, but the effect of eliminating the image that is conspicuous is small. FIG.
(F) is an example in which the embedded image is embedded using a deformed two-dimensional image. It is clear that the transformation includes various kinds of coordinate transformation such as a spherical coordinate form and an elliptical coordinate form, starting with translation and rotation of the whole.

Next, in order to suppress the influence on the three-dimensional object as in the two-dimensional image seen from the left eye shown in FIG. 3A, it is effective to further perform the following method for the above filling method. It is. That is, as shown in FIG.
It is effective to fill the embedded image described in (a) to (f) using a two-dimensional image with gradation applied. As the direction of the gradation, it is effective that the gradation becomes thinner on the side of the projected two-dimensional image of the three-dimensional object. In addition, it is conceivable that the direction is a horizontal direction, a vertical direction, and both directions. As a result, it is possible to suppress the influence on the three-dimensional object by obscuring the edge portion caused by overlapping with the image in front, thereby further improving the effect.

Further, it is clear that even an image quoted from a completely different place can be replaced by the image if it is similar to the embedded image as viewed from the observer 100. In the above embodiment,
Although the case where the person is directly facing and the eyes are in the left-right direction has been described, when the person's eyes are in the up-down direction (for example, when the head is tilted, etc.) Obviously, the above measures should be taken. Furthermore, it is effective to perform the above-described treatment not only in the left-right direction but also in the entire circumferential direction so as not to move in the direction of the human eye. As described above, the invention made by the inventor has been specifically described based on the embodiment. However, the present invention is not limited to the embodiment, and can be variously modified without departing from the gist of the invention. Of course, it is.

[0026]

The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows. According to the three-dimensional display device of the present invention, an unnecessary image that is pseudo-generated in the displayed image is removed,
Images can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of a tertiary display device according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a depth position between a three-dimensional object and a background image and a two-dimensional image displayed on each display surface according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating an image viewed from a right eye and a left eye according to the first embodiment of the present invention.

FIG. 4 is a diagram for explaining an embedded image according to the first embodiment of the present invention.

FIG. 5 is a diagram for explaining the principle of a conventional three-dimensional display method.

FIG. 6 is a diagram for explaining a pseudo-excessive and unnatural two-dimensional image generated in a peripheral portion of a three-dimensional object in a conventional three-dimensional display method.

[Explanation of symbols]

100: observer, 103, 207: three-dimensional object, 10
4,208 ... background object, 105, 106, 204, 20
5,206,209,1021,1022 ... two-dimensional image,
201 to 203, 1011 to 101n: display surface.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C061 AA06 AA29 AB12 AB17 5G435 AA00 BB02 BB04 BB06 BB12 BB15 CC11 DD01 FF05 GG03 GG08

Claims (12)

[Claims] 1. A two-dimensional image in which a display target object is projected from a direction of a line of sight of the observer on a plurality of display surfaces at different depth positions as viewed from the observer, and the generated two-dimensional image is generated. An image is displayed on each of a plurality of display surfaces at different depth positions as viewed from the observer, and the brightness of the displayed two-dimensional image is independently changed for each of the display surfaces to form a three-dimensional stereoscopic image. Wherein the display target object is located behind the three-dimensional object to be displayed and the three-dimensional object to be displayed as viewed from the observer, and a part of the display object is displayed. When the background object overlaps with the three-dimensional object to be displayed, the three-dimensional object to be displayed is displayed on the at least two display surfaces of at least two of the plurality of display surfaces from the viewing direction of the observer. First two-dimensional projection on surface Is displayed, on the rear display surface located behind the at least two display surfaces as viewed from the observer, in the two-dimensional image of the background object projected onto the rear display surface from the observer's line of sight. A display area of a second two-dimensional image including a portion that does not overlap with the three-dimensional object to be displayed, and a two-dimensional image obtained by projecting the three-dimensional object to be displayed on the rear display surface from the line of sight of the observer. A three-dimensional display method characterized by displaying at least an embedded image displayed in an area adjacent to the second two-dimensional image. 2. The three-dimensional display method according to claim 1, wherein the embedded image is an image other than a colorless and transparent image. 3. The three-dimensional display method according to claim 1, wherein the embedded image is an image other than black. 4. The three-dimensional display method according to claim 1, wherein the embedded image is an image other than white. 5. The embedded image is a two-dimensional image obtained by projecting a portion of the background object that overlaps the three-dimensional object to be displayed onto the rear display surface from the direction of the observer's line of sight. Item 3. The three-dimensional display method according to Item 1. 6. The embedded image is a two-dimensional image obtained by projecting a portion of the background object that overlaps the three-dimensional object to be displayed on the rear display surface from a line of sight of the observer,
The three-dimensional display method according to claim 1, wherein the images have similar brightness or transmittance. 7. The three-dimensional display method according to claim 1, wherein the embedded image is an image of an area of the second two-dimensional image adjacent to the embedded image. 8. The image processing apparatus according to claim 1, wherein the embedded image is an image of a region adjacent to the embedded image of the second two-dimensional image, the image having similar color, brightness, or transparency. 3D display method described. 9. The embedded image may be a two-dimensional image obtained by projecting a portion of the background object overlapping the three-dimensional object to be displayed on the rear display surface from a direction of a line of sight of the observer, or the second image. The three-dimensional display method according to claim 1, wherein the three-dimensional display method is a combination of an image of a region adjacent to the embedded image of the three-dimensional image or an image obtained by performing image processing. 10. The image subjected to the image processing is a two-dimensional image obtained by projecting a portion of the background object overlapping the three-dimensional object to be displayed from the direction of the observer's line of sight to the rear display surface,
10. The tertiary image according to claim 9, wherein the image of the area adjacent to the embedded image of the second two-dimensional image includes an image obtained by averaging, blurring, deforming, repeating, or mapping conversion. Original display method. 11. The embedded image is displayed on the back of the first two-dimensional image and the three-dimensional object to be displayed from the direction of the observer's line of sight, based on the parallax between the right and left eyes of the observer. The three-dimensional display method according to any one of claims 1 to 10, wherein the display is performed in an area where the two-dimensional image projected onto the surface is not completely overlapped and is shifted. 12. The embedded image may be an image whose luminance is gradually decreased or an image whose luminance is gradually increased from a boundary with the second two-dimensional image toward a center of the display area. The three-dimensional display method according to claim 11, wherein: