JP3483276B2 - Three-dimensional image display method and apparatus - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses a computer to
The present invention relates to a three-dimensional image display method and apparatus for displaying a three-dimensional image.

[0002]

2. Description of the Related Art Conventionally, a technique for displaying a three-dimensional image by computer graphics has been developed. As a method in such an image display technique, (1) a method of describing an object shape by a fixed square grid fixed on a distance image and performing three-dimensional display, (2) A method of creating one piece of adaptive polygon data in which the polygon is changed from the range image data, describing the shape of the object by this polygon data, and performing three-dimensional display,
(3) A method for generating an equidistant square grid from shape data such as a curved surface described by the shape modeler, describing the shape of the object with it, and performing three-dimensional display. There is a method of describing and directly displaying it in three dimensions.

[0003]

However, in the above methods (1) and (3), since the shape of an object is described by a uniform polygon, the polygon is finely divided in order to express a complicated surface shape. However, it is necessary to increase the number of polygons. However, if the number of polygons is increased, an excessive number of polygons will be used to describe a uniform surface shape such as a large plane. For this reason,
It consumes a large amount of memory and causes a problem in display processing speed and the like.

Further, in the above methods (2) and (4), since the size of the polygon is changed according to the surface shape of the display object, there is a problem when the shape is expressed by the uniform polygon. The point has been resolved. However, with the above four methods, even when the observer does not need to display the detailed shape of the object, such as when the observer moves or rotates the displayed object, the details are displayed according to the shape data. Resulting in. For this reason, there is a problem in that the display device is unnecessarily loaded, and it becomes impossible to smoothly rotate and move in response to an observer's request.

Further, even when the observer is not rotating or moving the object, according to the above-mentioned methods, when the size of the object on the display screen is small depending on the viewpoint set by the observer (that is, Even if the angle of view is small), the detailed shape of the object is displayed regardless of the resolution of the display device and the visual resolution of the observer, which imposes an unnecessary load on the display device.

The present invention has been made in view of the above problems, and the surface shape of a display target or the movement of a display image is displayed.
An object of the present invention is to provide a three-dimensional image display method and apparatus capable of three-dimensionally displaying a target object by changing the resolution based on the above.

[0007]

The three-dimensional image display method of the present invention for achieving the above object comprises the following steps. That is, for displaying a three-dimensional image of the display object ,
The size of the polygon is adjusted according to the surface shape of the display object.
A storing step of plural kinds stored in the shape data is changed to応的 different resolutions, in a three-dimensional image display when the display object, while moving the display of the display object,-out the dynamic <br/> Accordingly, a determination step of determining the resolution of the shape data suitable for use in the three-dimensional image display and a display step of performing the three-dimensional image display using the shape data of the determined resolution are provided.

A three-dimensional image display method of the present invention for achieving the above object has the following configuration. That is, the resolution is increased by performing an input step of inputting the three-dimensional geometric shape information regarding the three-dimensional shape of the display target and a process including smoothing and thinning on the three-dimensional geometric shape information input by the input step. A creating step of creating a plurality of different shape data, a storing step of storing the plurality of shape data created by the creating step, and a three-dimensional image to be displayed.
The image to be displayed is being moved during image display
In the meantime, in accordance with the movement, the shape data is selected from the plurality of shape data stored in the storing step in order to change the resolution of the shape data suitable for use in three-dimensional image display, and the shape data is selected. And a display step of performing three-dimensional display of the display target with shape data.

[0009]

With the configuration or process described above, a plurality of types of shape data for displaying a three-dimensional image of a display object are stored at different resolutions. And the 3D image to be displayed
When displaying, move the display (image) of the display target
While the image is moving, the resolution of the shape data suitable for displaying the three-dimensional image is determined (or changed) according to the movement, and the three-dimensional image is obtained using the shape data having the determined (or changed) resolution. Display.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1> In the image display apparatus according to the present embodiment, a uniform polygon such as range image data is obtained as three-dimensional shape information representing the shape of a display object from a range image input device, a range image database, a shape modeler and the like. Enter the data. Further, the attribute information indicating the material of the display target object for specifying the surface state of the display target object is input.

Shape data representing the target shape is generated from the input three-dimensional shape information (uniform polygon data). In this embodiment, adaptive polygon data is used as the shape data. The adaptive polygon data is polygon data in which the size of the polygon is adaptively changed according to the surface shape of the display target object. Furthermore, in this example, the layered adaptive polygon data composed of a plurality of adaptive polygon data obtained by gradually changing the highest resolution included in the adaptive polygon data is stored in the storage medium.

Then, the partial surface shape of the display object
Depending on the performance of the display device, the appearance of the object on the display device, the rotation and movement of the displayed image, and other requirements of the observer, the hierarchy of the layered adaptive polygon data that represents the object is automatically selected. , A three-dimensional image is displayed so that the viewer does not feel uncomfortable. For example, the rotation of the object requested by the observer on the display device
Three-dimensional display of the target object is performed by switching the hierarchy of the layered polygon data based on the ratio (angle of view) of the target object in the entire visual field due to movement or movement of the viewpoint. In this way, by switching the resolution of the three-dimensional image according to the display state, it is possible to smoothly rotate and move the image.

The three-dimensional image display device of the first embodiment will be described in detail below.

FIG. 1 is a block diagram showing the basic structure of a three-dimensional image display device according to this embodiment. In the figure,
Reference numeral 1 denotes a storage device for storing the processing procedure, and a control program represented by the flowcharts described later with reference to FIGS. 2 and 4 is also stored here. Reference numeral 2 denotes a storage device for storing information necessary for processing and input / output data, in which layered adaptive polygon data and the like described later in FIG. 3 are stored. Reference numeral 3 is a CPU, which executes processing in accordance with the processing procedure stored in the storage device 1. A display (CRT) 4 displays information necessary for processing and a three-dimensional image. Reference numeral 5 is a line-of-sight input device, which is a CR of the observer's viewpoint.
The three-dimensional position and direction with respect to T4 are detected. Reference numeral 6 denotes a valuator, which is an apparatus for inputting instructions such as rotation and movement of an object from an observer. Reference numeral 7 is a keyboard for inputting data and instructions from the user, and 8 is a mouse for inputting instructions on the CRT 4. An input / output interface 9 is connected to an external distance image input device, a distance image database, and a geometric modeler device (shape modeler device) via the input / output interface to generate uniform polygon data obtained by sampling a three-dimensional object at uniform intervals. Captured.

FIG. 2 is a flow chart showing the flow of processing for creating layered adaptive polygon data in this embodiment. In the figure, arrows indicate the direction of data flow.

First, in step S210, an input device such as a range image measuring device, a range image database, a geometric modeler device, or the like is used to input 3 from the input / output interface 9.
The uniform polygon data representing the three-dimensional object shape is read. In this example, all-round distance image data as shown in FIG. 5 is used as the uniform polygon data.

Here, the omnidirectional distance image is one of image data for imaging the result of measuring the distance to the target object, and when measuring the distance, the object such as the object is rotated or It is the image data obtained by measuring the shape information and the position information in the entire circumferential direction of the object by rotating the measuring device. The omnidirectional distance image used in this embodiment is image data having a data structure as shown in FIG. That is, an arbitrary straight line is set as the rotation axis, and the measurement points are arranged around the rotation axis as shown in FIG.
It is obtained by storing the distance data at that point in the two-dimensional memory of FIG. 6 (b).

Next, in step S220 of FIG. 2, N (N> 1) uniform polygon data having different resolutions are created from this uniform polygon data. At this time, which shape of the uniform polygon data is to be created is determined by examining the shape of the target object. Generally, a surface has a complicated shape, and an object composed of curved surfaces having various curvatures requires polygon data of many kinds of resolutions.

The basic procedure for creating a plurality of uniform polygon data in step S220 of this embodiment is as follows. First, the read all-round distance image data (referred to as original uniform polygon data) is set to the highest resolution, and this is smoothed and thinned to create a lower resolution all-round distance image. At this time, by changing the smoothing range and the thinning interval, it is possible to create omnidirectional range images having different resolutions. More specifically, a low-pass filter is used to remove noise from the input uniform polygon data and generate uniform polygon data including a curvature component in a predetermined range. As an example of a low-pass filter for this purpose, in this example, Gaussian (Gauss) is used.
ian) filter is used.

Next, in step S230, a normal vector is calculated in the uniform polygon data of each resolution obtained in step S220 (step 23).
0). The normal vector is obtained by plane-approximating the three-dimensional data of points in the polygon data that are in the neighborhood relationship by the least square method.

Then, in step S240, an edge is extracted from the uniform polygon data of each resolution and the normal vector, and the edge map {E1, E2, ..., EN is used.
} Is generated. The edge map is ridge line data representing the boundary between polygons whose normal vector has changed by a predetermined amount or more. As an example of the processing procedure of this step, there is a method disclosed in Japanese Patent Application No. 4-321636, and a method similar to this can be used.

When extracting an edge from each uniform polygon data, the angle between the normal vectors of adjacent pixels, whether it is low resolution uniform polygon data or high resolution uniform polygon data. An edge is provided in a portion where is a value greater than or equal to a certain value. As a result, the curvature is proportional to the sampling interval, and a smooth-shaped edge map can be extracted from each low-resolution uniform polygon data, and a fine-shaped edge map can be extracted from each high-resolution uniform polygon data.

Next, in step S250, the edge maps of the respective resolutions obtained in the previous step S240 are ORed and combined to generate adaptive polygon data of the respective resolutions. At this time, processing for correcting the contradiction in which the ridgeline elements intersect and the isolated ridgeline element are performed. An example of the processing procedure of this step is disclosed in Japanese Patent Application No. 4-325554 and Japanese Patent Application No. 5-159549, and methods similar to these can be used. However, in this embodiment, unlike the techniques described in these specifications, data of multiple resolutions is not combined into one integrated edge map. That is, as shown in step S250 of FIG. 2, the edge map E1 having the lowest resolution and the edge map E2 having the second lowest resolution are combined to generate an integrated edge map R1.
And an edge map E3 having the third lowest resolution are combined to create an integrated edge map R2, and so on. By repeating this process, N−1 integrated edge maps {R1,
R2, ..., RN-1} are created.

Each of the integrated edge maps described above represents an object by a large number of polygons. Step S260
Then, each polygon is divided into triangles.
Then, in step S270, step S260
The final adaptive polygon data is generated by referring to the three-dimensional coordinate value and the normal vector of the pixel located at the apex of each triangle obtained in (3). An example of this method is the method described in Japanese Patent Application No. 5-159549.

FIGS. 7 and 8 are diagrams showing, as wire frames, the adaptive polygon data obtained from the omnidirectional distance image of FIG. In FIG. 7A, the edge map data of the uniform polygon data obtained by thinning out the pixel interval to 32 dots and the edge map data of the uniform polygon data obtained by thinning out the pixel interval to 16 dots are integrated. This is the adaptive polygon data obtained. Further, FIG. 7B
7A is adaptive polygon data obtained by integrating the integrated edge map data of FIG. 7A and the edge map data of uniform polygon data obtained by thinning out pixel intervals to 8 dots. Similarly, FIG. 8A corresponds to FIG. 7B.
The integrated edge map data of FIG. 8A and the integrated edge map data of FIG. 8A are obtained by integrating the edge map data obtained by thinning out the pixel interval to 4 dots. It is obtained by integrating the edge map data obtained by thinning the pixel interval to 2 dots. In this way, polygon data having different resolutions are arranged according to the curved surface shape.

Finally, in step S280, these N-1 pieces of adaptive polygon data are combined into one data in the format shown in FIG. 3 and stored in the storage device 2 as hierarchical adaptive polygon data.

FIG. 3 is a diagram showing a data structure example of the layered adaptive polygon data stored in the storage device 2. In the figure, 31 is vertex data, and step S260
This is data in which the identifier (ID1) is added to the vertex coordinates (X, Y, Z) of all the triangles obtained in. Reference numeral 32 is a delimiter, which represents a delimiter of each data. 33 is resolution 1
Of the adaptive polygon data, and one triangle is represented by a set of three identifiers of vertex coordinates. Reference numeral 34 denotes adaptive polygon data having a resolution of 2, and, like the polygon data 33 having a resolution of 1, is a set of data in which identifiers of three vertex data forming a triangle are set as one set. Reference numeral 35 is a code representing the end of the layered adaptive polygon data.
In this way, since the adaptive polygon data for each layer is stored only by the vertex coordinate identifier, the storage capacity is saved.

Next, the procedure for displaying the layered adaptive polygon data stored in the storage device 2 will be described with reference to the flowchart of FIG. The layered adaptive polygon data stored in the storage device 2 as described above is three-dimensionally displayed according to the flow of processing shown in FIG.

First, the layered adaptive polygon data is read from the storage device 2 of FIG. 1 (step S410). Next, the resolution I is set to the initial resolution (step S42).
0), the adaptive polygon data of the resolution I is displayed three-dimensionally (step S430). At this time, the initial resolution is displayed at the highest resolution (N-1). Alternatively, step S46 is performed based on the ratio (angle of view) of the display target on the screen.
The resolution determined by the method shown in 0 may be used. still,
Step S460 will be described later.

Next, the processing is in a state of waiting for an instruction (event) from the observer (steps S441 to S).
445). The event is input from the valuator 6 and the mouse 8 as information on the movement of the observer's viewpoint obtained from the line-of-sight input device 5 of FIG. The input event is rotation / movement with respect to the object, or movement of the viewpoint position (step 4
41), the process proceeds to step S450.

In step S450, it is determined whether or not the rotation / movement is in the start state, and if it is in the start state, the resolution immediately before the start is saved, and then the resolution of the image is reduced by one step.
If it is already rotating / moving, the resolution is simply reduced by one step. As an example of the processing procedure, in step S451, it is determined whether or not the rotation / movement start state (J = 0) is satisfied.
If = 0, then in step S452, the current resolution I is set in J and the current resolution I is reduced by one step (step S
453). If the rotation / movement continues (J ≠ 0),
The process directly proceeds to step S453, and one of the current resolutions is dropped.

If the input event is the enlargement of the object or the approach of the viewpoint position, the process proceeds from step S442 to step S460. In step S460, the viewing angle (that is, the angle of view) at which the region where the object is to be newly displayed occupies the field of view of the observer is roughly estimated, and the value K satisfying the condition shown in step 461 is obtained from the angle and is calculated as Set as the resolution. Here, t1 is the interval of the angle of view required for changing the predetermined display resolution. Even when the input event is reduced with respect to the object or the viewpoint position moves away, the process proceeds from step S443 to step S460 and the above-described processing is performed.

When the input event disappears and the object or viewpoint changes from the rotating / moving state to the stationary state, the process proceeds to step S470. If the state immediately before the stationary state is the rotating state (that is, J ≠ 0), the resolution is returned to the resolution J before the rotating state, and J
Is reset to 0 (step 470).

Steps S450 and S46 described above
0, when a new resolution is set in step S470, the process proceeds to step S480. In step S480,
When the newly set resolution exceeds the resolution limit of the display device to display fine polygons, the resolution is lowered so that all the polygons do not exceed the resolution limit of the display device (step S480). ). Further, in step S490, the correctness of the new resolution is verified, and a new three-dimensional display of the target object is performed using the adaptive polygon data of the resolution I. That is, in step S490, it is checked whether the set resolution exceeds the minimum resolution and the maximum resolution of the layered adaptive polygon data stored in the storage device 2. If it is lower than the lowest resolution, set it to the lowest resolution, and if it is higher than the highest resolution, set it to the highest resolution again.

As described above, FIGS. 7 and 8 show the wire adaptive display of the four-stage hierarchical adaptive polygon data obtained by this embodiment. 9 and 10
Shows the data corresponding to the adaptive polygon data shown in FIGS. 7 and 8 in a shaded display. In an actual display device, these layered adaptive polygon data are switched and displayed according to the processing shown in the flowchart of FIG.

In the embodiment shown in FIG. 1, not all of the input devices indicated by reference numerals 5 to 8 are necessary, and other methods and devices can be substituted. For example, the following device can be applied to the line-of-sight input device 5. For example, the HMD (He
A line-of-sight detection device 81 is added in the vicinity of both eyes (ad Mounted Display) to detect the movement of the line-of-sight during image display, and the process of step 450 of FIG. It can operate. Here, as the line-of-sight detection device 81, for example, one used in an autofocus camera or the like can be applied. Further, as shown in FIG. 12, a television camera 9 is provided on the CRT 4 of FIG.
1 may be attached, and the movement of the line of sight may be detected by tracking the position of the eyes of the observer who is facing the CRT 4 with this television camera 91. As a result, while the line of sight is moving, FIG.
By performing the process of step 450, further calculating the angle of view by calculating the distance from the distance between the eyes to the rough viewpoint, and performing the process of step 460, the same operation as that of the first embodiment can be performed.

As described above, according to the above-described embodiment, the size (resolution) of the polygon is changed in accordance with the partial shape of the display object, so that even when the shape is faithfully expressed. It is possible to prevent the number of polygons from unnecessarily increasing.

Further, according to the present embodiment, since one display object has a plurality of polygon data having different resolutions, the resolution is changed and displayed in accordance with an instruction such as rotation and movement of the observer. Is possible. For this reason, when the observer does not need to express the detailed shape, such as during rotation of the object, the resolution is reduced so as not to express the unnecessary detailed shape, so that the rotation and movement of the object can be smoothly performed. It becomes possible to display.

Further, according to the present embodiment, the position and the direction of the display with respect to the observer are used to calculate the angle occupied by the display object in the visual field when the object is displayed, and the angle of the display image is calculated accordingly. It is possible to change the resolution.
Therefore, the load on the display device can be reduced by switching the resolution of the polygon data depending on whether the target object is displayed small on the screen or displayed large.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of one device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0042]

As described above, according to the three-dimensional image display method and apparatus of the present invention, it becomes possible to display the target object three-dimensionally by changing the resolution based on the display state. The added load can be reduced, and smooth display can be performed when moving or enlarging / reducing the display image.

[0043]

[Brief description of drawings]

FIG. 1 is a block diagram showing a device configuration of a three-dimensional display device of this embodiment.

FIG. 2 is a flowchart showing the flow of processing for creating layered adaptive polygon data according to the present embodiment.

FIG. 3 is a data format of layered adaptive polygon data used in this embodiment.

FIG. 4 is a flowchart showing a flow of display processing of layered adaptive polygon data according to the present embodiment.

FIG. 5 is a diagram showing an all-round type range image used for an experiment in this example.

FIG. 6 is a schematic diagram of an all-round type distance image in the present embodiment.

FIG. 7 is a diagram in which the layered adaptive polygon data created in this embodiment is three-dimensionally displayed in a wire frame.

FIG. 8 is a diagram in which the layered adaptive polygon data created in the present embodiment is three-dimensionally displayed in a wire frame.

9 is a diagram in which the layered adaptive polygon data shown in FIG. 7 is three-dimensionally displayed with shading.

FIG. 10 is a diagram in which the layered adaptive polygon data shown in FIG. 8 is three-dimensionally displayed with shading.

FIG. 11 is a diagram illustrating an appearance of a line-of-sight input HMD (Head Mouted Display).

FIG. 12 is a diagram illustrating another example of the line-of-sight input device.

[Explanation of symbols] 1, 2 storage device 3 CPU 4 Display (CRT) 5 Line-of-sight input device 6 valuator 7 keyboard 8 mice 9 I / O interface

Front Page Continuation (72) Inventor Toshikazu Oshima 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) Reference JP-A-4-15772 (JP, A) JP-A-63-155366 ( JP, A) JP 63-83871 (JP, A) JP 5-101189 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G06T 15/00

Claims (20)

(57) [Claims] 1. The size of a polygon for displaying a three-dimensional image of a display object according to the surface shape of the display object.
A storing step of storing a plurality of types of shape data adaptively changed at different resolutions ; and
While moving the display of, the determination step of determining the resolution of the shape data suitable for use in the three-dimensional image display according to the movement, and the three-dimensional image display using the shape data of the determined resolution. A three-dimensional image display method, comprising: 2. An input step of inputting three-dimensional geometric shape information about a three-dimensional shape to be displayed, and a process including smoothing and thinning out on the three-dimensional geometric shape information input by the input step. A creating step of creating a plurality of shape data having different resolutions, a storing step of storing the plurality of shape data created by the creating step, and an image of the display target when displaying a three-dimensional image of the display target.
While moving the image, the shape data is selected from the plurality of shape data stored in the storing step so as to change the resolution of the shape data suitable for use in three-dimensional image display according to the movement. And a display step of performing a three-dimensional display of the display target with the selected shape data. 3. In the input step, distance image data of a display target is input, and the distance image data of the display target is input from the distance image data.
The three-dimensional image display method according to claim 2, wherein three-dimensional geometric shape information representing a three-dimensional shape is generated. 4. The three-dimensional image display method according to claim 2, wherein in the input step, three-dimensional shape information is manually input. 5. The polygon data in the creating step is adaptive polygon data that adaptively changes the size and shape of the polygon according to the partial shape of the display target. 3D image display method. 6. The hierarchized adaptive polygon data composed of a plurality of adaptive polygon data obtained by stepwise changing the maximum resolution included in the three-dimensional geometric shape information. The three-dimensional image display method according to claim 5. 7. The data storage method according to claim 6, wherein the storing step removes and stores data in which the vertices and sides of the polygon shared in the layered adaptive polygon data are removed.
The three-dimensional image display method described in [3]. 8. The three-dimensional image display method according to claim 1, wherein the movement of the image of the display target is movement or rotation of the target according to a user's request. 9. The display step selects a layer of the layered adaptive polygon data based on an angle of view from an observer occupied by the display target on a two-dimensional projection surface onto which the display target is projected, 7. The three-dimensional image display method according to claim 6, wherein the display target is displayed based on the adaptive polygon data of the selected layer. 10. The display step comprises: on a two-dimensional projection plane onto which the display target is projected, the layered adaptive polygon data according to the size of the display target projected and the resolution of the display device on the projection surface. The three-dimensional image display method according to claim 6, wherein a hierarchy is selected and displayed. 11. A polygon size according to a surface shape of a display object for displaying a three-dimensional image of the display object.
A storage unit for storing a plurality of types of shape data adaptively changed at different resolutions ; and a display target when displaying a three-dimensional image of the display target.
While moving the display, in response to the motion, the three-dimensional image display using a determining means for determining the resolution of the shape data suitable for use in the three-dimensional image display, the shape data of the determined resolution A three-dimensional image display device, comprising: 12. An input unit for inputting three-dimensional geometric shape information on a three-dimensional shape to be displayed, and a process including smoothing and thinning for the three-dimensional geometric shape information input by the input unit. A creating means for creating a plurality of shape data having different resolutions, a storing means for storing the plurality of shape data created by the creating means, and an image of the display target when displaying a three-dimensional image of the display target.
While moving the image, the shape data is selected from the plurality of shape data stored in the storage means so as to change the resolution of the shape data suitable for use in displaying a three-dimensional image in accordance with the movement. And a display unit that performs three-dimensional display of the display target with the selected shape data. 13. The input means inputs distance image data of a display target and generates three-dimensional geometric shape information representing a three-dimensional shape of the display target from the distance image data. The three-dimensional image display device according to item 1. 14. The three-dimensional image display device according to claim 12, wherein the input unit manually inputs three-dimensional shape information. 15. The polygon data in the creating means is adaptive polygon data that adaptively changes the size and shape of the polygon according to the partial shape of the display target. 3D image display device. 16. The creation means creates a hierarchical adaptive polygon data composed plurality of adaptive polygon data obtained by gradually changing the highest resolution included in the three-dimensional geometry information 3-dimensional image display apparatus according to claim 15, characterized in that. 17. The three-dimensional structure according to claim 16, wherein the storage unit removes and stores data in which the vertices and sides of a polygon shared in the layered adaptive polygon data are removed. Image display device. 18. The three-dimensional image display device according to claim 11, wherein the movement of the image to be displayed is movement or rotation of the object according to a user's request. 19. The display means selects a layer of the layered adaptive polygon data based on an angle of view from an observer occupied by the display target on a two-dimensional projection surface onto which the display target is projected, The three-dimensional image display device according to claim 16, wherein the display target is displayed based on the adaptive polygon data of the selected layer. 20. On the two-dimensional projection surface on which the display object is projected, the display means stores the layered adaptive polygon data according to the size of the display object projected and the resolution of the display device on the projection surface. The three-dimensional image display device according to claim 16, wherein a hierarchy is selected and displayed.