JP2001078233A - Space drawing method, virtual space drawing device, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain drawing of high real time property by storing space data in 1st format in a 1st memory, downloading space data of a virtual object within a predetermined range from a detected current viewpoint position from the 1st memory to a 2nd memory when the space data are not present in the 2nd memory, and drawing a virtual space according to the space data in the 2nd memory. SOLUTION: When ray space data corresponding to a viewpoint position are not present in a memory 27 yet, billboard image are used instead. The ray space image, however, is given priority to the billboard. Namely, a virtual image of an arbitrary viewpoint position can be generated with high precision on the basis of the ray space data from specific viewpoint position. Therefore, when the ray space data are present in the memory 27, the virtual image is generated according to the current viewpoint position and presented on a CRT.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a space drawing method, a virtual space drawing device, and a storage medium for decoding a large amount of compressed image data such as ray space theoretical data and drawing the same in a virtual space.

[0002]

2. Description of the Related Art A number of techniques have been proposed for describing and expressing a virtual space not on the basis of a three-dimensional geometric shape but on the basis of a real image. These are Image Based Rendering
(Hereinafter abbreviated as IBR), which is characterized by the fact that it can represent a highly realistic virtual space that cannot be obtained from a method based on a three-dimensional geometric shape because it is based on a real image. .

[0003] Attempts have been made to describe a virtual space based on ray space theory, which is one method of IBR. For example, IEICE Transactions on "Realization of Virtual Environment by Fusion of CG Model and Ray Space Data" (D-11, Vol. J80-D-
11 No. 11, pp3048-3057, November 1997) or "3
Interconversion between hologram and ray space for three-dimensional integrated image communication "(3D Image Conference).

[0004] The ray space theory will be described.

As shown in FIG. 1, a coordinate system OXY-
Install Z. A ray passing through a reference plane P (Z = z) perpendicular to the Z axis is represented by a position (x, y) where the ray crosses P and variables θ and φ indicating the direction of the ray. That is, one ray is uniquely determined by five variables (x, y, z, θ, φ). If a function representing the light intensity of this light beam is defined as f, the light beam data in this space can be represented by f (x, y, z, θ, φ). This five-dimensional space is called “ray space”
Call. More generally, the time variation t may be inserted, but is omitted here.

Here, if the reference plane P is set to z = 0 and the disparity information in the vertical direction of the light ray, that is, the degree of freedom in the φ direction is omitted, the degree of freedom of the light ray is reduced to two dimensions (x, θ). Can be done. This x-θ two-dimensional space is a subspace of the ray space. Then, a ray (FIG. 2) passing through a point (X, Z) in the real space is represented by u = tanθ in the xu space as shown in FIG.

[Equation 1] X = x + u · Z

Are mapped on a straight line. Shooting with a camera corresponds to an operation of receiving a light beam passing through the lens focal point of the camera on an imaging surface and imaging the brightness and color of the light. In other words, it means that a group of rays passing through one point in the real space, that is, the focal position, has been acquired for the number of pixels as images. Here, the degree of freedom in the φ direction is omitted, and the behavior of light rays only in the XZ plane is considered. Therefore, only pixels on a line segment that intersects the plane orthogonal to the Y axis in the image will be considered. Become. As described above, light rays passing through one point can be collected by photographing an image, and data on one line segment in the xu space can be acquired by one photographing.

When this photographing is performed at many different viewpoint positions (in this specification, unless otherwise specified, the viewpoint position includes both the viewpoint position and the line-of-sight direction), a group of rays passing through many points is obtained. Can be acquired. As shown in FIG.
When the real space is photographed using two cameras, the nth (n =
According to the focal position (X _n , Z _n ) of the camera C _n of (1, 2,..., N), as shown in FIG.

[Equation 2] x + Z_nu = X_n  Can input data on a straight line. like this
By taking pictures from a sufficiently large number of viewpoints,
The xu space can be densely filled with data.

Conversely, a new observation image from an arbitrary viewpoint position can be generated from the data in the xu space (FIG. 6) (FIG. 7). As shown in this figure, the observation image from a new viewpoint position E (X, Z) expressed in the form of an eye is:
It can be generated by reading out the data on the straight line of Expression 1 in the xu space from the xu space.

[0012]

The actual photographed image data such as the above-mentioned ray space data is usually set for each unit (for example,
Compressed for each object) and stored in an external storage device or the like. Therefore, in order to draw such spatial data in a virtual space, it is necessary to download the data to the main storage device, decode the data, and draw the data on the main storage device. On the other hand, the user can grasp the virtual space only after the virtual images of all the virtual objects to be drawn in the virtual space are displayed. Therefore, if there are a plurality of objects to be rendered, the user must download, decode, and render all spatial data for those objects,
These virtual objects cannot be grasped. That is, for example, when the user walks through such a virtual space, the rendering apparatus has a poor response.

This is the first problem associated with the prior art in handling spatial data such as ray spatial data.

A second problem with the prior art is that real image data such as ray space data contains a large amount of data. Such data is usually in the form of a database,
Usually, the image data is stored away from the image processing device. For this reason, the image processing device must download a large amount of spatial data to the image processing device in order to develop the virtual image in the virtual space. Must be kept. Due to the enormous volume of real image data, the turnaround time from requesting spatial data to being able to render the spatial data in the image processing device, even though the communication speed has improved recently, Is too long to overlook. Therefore, the inventors have come to recognize that in a system for presenting such a virtual space to a user, it is necessary to keep the user from being bored while waiting for the use of real image data. . That is, during this waiting time, a scene from an arbitrary viewpoint position cannot be obtained, but a billboard image (one image) having a short download time is substituted.

A third problem related to the prior art is that when providing a walk-through system that can freely go around in a virtual space using real image data such as ray space data, the memory capacity of the system is limited. Occurs when there is. That is, in order to address the first problem described above, a method of dividing a virtual space into a plurality of sub-spaces (for example, in a virtual museum, each exhibition room constitutes one sub-space) is proposed. Can be.

That is, when it is detected that the user is approaching a certain exhibition room, the time required for the transfer process prior to the drawing process can be reduced by pre-reading the spatial data of only that exhibition room. I do. Further, when the user intends to leave the exhibition room (sub space A), the spatial data for the next sub space (for example, the exhibition room B) is stored, and the spatial data of the exhibition room A is stored until then. It is necessary to overwrite the storage area that has been used. By doing so, even if the memory capacity is relatively small, the sub-virtual space of the exhibition room can be successively reproduced at a speed close to real time.

Incidentally, this pre-reading is determined based on the fact that the user's viewpoint position has approached the target subspace.
However, the movement of the user's viewpoint position does not mean that a highly accurate route guidance is performed because a mouse or the like is used. Therefore, the user may be invited to an incorrect route. That is, the viewpoint position of the user who is not in the pre-reading start area is
If the system detects that it is in the prefetch start area by mistake, the system starts prefetching. In particular, when the user's viewpoint is moved near the pre-reading start zone, this malfunction is likely to occur. For example, as shown in FIG. 8, when an operation is performed such that the viewpoint position enters the pre-reading start zone from the exhibition room space and returns to the exhibition room space again, the erroneous pre-reading operation is performed. And the large volume of spatial data for the exhibition room space is purged (erased) and returned to the exhibition room space again (this is a situation that occurred because the viewpoint position was erroneously detected. Is not conscious of returning), it is necessary for the system side to transfer the data of this exhibition room space again. This is a wasteful operation in terms of time.

The present invention addresses the first problem.

That is, a first object of the present invention is to temporarily download a large amount of spatial data stored in a memory such as an external storage device and draw a virtual space based on the downloaded spatial data. We propose a space drawing method and a drawing device that enable space drawing with high real-time properties.

Further, a second object of the present invention is to provide a space drawing method and a drawing apparatus which enable real-time space drawing when a coded space data is once decoded to draw a virtual space. suggest.

[0021]

According to the first aspect of the present invention, there is provided a space drawing method for drawing a virtual space viewed from an arbitrary viewpoint position, in order to achieve the first object. Is stored in the first memory, the current viewpoint position is detected, and the spatial data of the virtual object within a predetermined range from the detected current viewpoint position does not exist in the second memory. In some cases, the spatial data is downloaded from the first memory to the second memory, and a virtual space is drawn based on the downloaded spatial data in the second memory.

According to the method of the first aspect, real-time responsiveness is maintained by limiting spatial data to be downloaded to spatial data close to the current viewpoint position.

However, even if the spatial data to be downloaded is limited to the spatial data close to the current viewpoint position, it takes time to download. Unless the download is completed, the target spatial data cannot be drawn. Therefore, according to the method of claim 2, spatial data of the virtual object in the virtual space is stored in advance in the second memory as spatial data of a second format different from the first format, and From the first memory to the second
While downloading to the memory of the second format, the virtual space is drawn based on the space data of the second format in the second memory. That is, the spatial data of the second format is used as a substitute image during downloading.

If the capacity of the second type of spatial data is large, the capacity of the required memory may be unnecessarily increased. Therefore, according to the method of claim 3, the spatial data in the first format is spatial data based on a real image, and the spatial data in the second format is billboard image data. The billboard image data has the characteristic that the reproduction degree is inferior, but the required memory amount is small.

It is not economical to keep the downloaded spatial data even when it is no longer needed. Therefore, according to the method of claim 4, the current viewpoint position is already the second viewpoint position.
When the distance from the viewpoint position corresponding to the spatial data stored in the second memory is more than a predetermined distance, the stored spatial data is released from the second memory.

According to a preferred embodiment of the present invention, the first memory is an external memory and the second memory is an external memory.
Is a main memory.

Even billboard image data requires memory capacity. Therefore, according to the method of claim 6, the billboard image data is stored in the first memory in advance, and the billboard image data in the first memory is converted to the billboard image data before drawing the virtual space. Download in advance to the second memory.

According to a preferred aspect of the present invention, a virtual walk-through environment is provided to a user in the virtual space.

According to a preferred aspect of the present invention, the predetermined range indicates a virtual object within a predetermined distance from the detected current viewpoint position. Regardless of the gaze direction, the probability that the downloaded spatial data is truly necessary spatial data increases.

It is preferable that the virtual space is subdivided into predetermined units from the viewpoint of reducing the required memory amount. Therefore, according to claim 31, the detected virtual object within a predetermined range from the current viewpoint position includes a virtual object in the sub-virtual space within the predetermined range from the current viewpoint position.

A space drawing method for drawing a virtual space viewed from an arbitrary viewpoint position for achieving the second object is as follows.
The first type of spatial data of the virtual object in the virtual space is compressed and stored in the internal memory, and the current viewpoint position is detected, and the internal memory is within a predetermined range from the detected current viewpoint position. When the compressed spatial data of the virtual object exists but the decoded spatial data does not exist, the compressed spatial data is decoded, and the virtual space is drawn based on the decoded spatial data. And

The first and second objects are as described in claim 1.
The present invention is also achieved by an apparatus to which the method of any one of Examples 14 to 30, 30 and 31 is applied, and further by a storage medium of the computer program.

[0033]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An image drawing apparatus and an image drawing method according to an embodiment in which the present invention is applied to a walk-through experience in a virtual space will be described in detail. These embodiments have sufficient memory to allow for data (r
a walk-through system (first embodiment) having a main memory only for storing ay space data (hereinafter, sometimes abbreviated as RSD), and a small main storage device inside,
An embodiment (second embodiment) in which the storage area is reserved and the storage area is released repeatedly because there is no capacity to store all the space data will be described.

FIG. 9 shows the configuration of the image processing system of the embodiment. The hardware configuration shown in FIG. 9 is a configuration of a normal workstation. That is, the hardware configuration itself is not different from a normal workstation.

This system provides a user with a virtual space CR
It is presented on T23. The user operates the mouse 28 to freely walk through the virtual space,
An object in the virtual space can be operated (moved, rotated, or enlarged). That is, the object in the virtual space is converted into ray space data based on the real image and
5 is stored in advance, but when the viewpoint moves as the walk-through occurs, an image that can be observed at the moved viewpoint is generated as described in FIG. 7, and the conventional CG data based on the geometric model is rendered. The generated image is combined with the generated image and displayed on the CRT 23.

The RSD database 29 has a large-capacity memory and stores ray space data of the entire space. The billboard image database 31 stores a plurality of billboard images. Here, billboard image data is, for example, image data of an object observed from a certain viewpoint position, and the amount of data is extremely small as compared with ray space data.

As described above, when the transfer of the ray space data from the database 29 cannot be made in time, this billboard image is provided to the user instead.

Reference numeral 32 denotes a joystick for instructing the user to move the viewpoint position.

FIG. 10 shows a virtual space formed by the first embodiment and the second embodiment. This virtual space is a sub virtual space,

Zone A, Zone B, Zone C, Zone D, Zone E

5 zones. In FIG. 10, for convenience of explanation, only zone A and zone B are shown in detail. The boundary of each zone (sub-virtual space) is shown to the user by a dashed line. The movement path (walk-through path) of the user's viewpoint position is indicated by a thin solid line. In one zone, a rectangular “wall” representing a virtual exhibition room is indicated by a thick solid line. Each exhibition room has four doorways, from which
The user can virtually enter and exit each exhibition room.

<First Embodiment> FIG. 11 shows the structure of an image processing apparatus according to the first embodiment. The feature of the first embodiment is that when preparation of ray space data cannot be made in time, for example, a billboard is installed at a position where a ray space data object is arranged in a virtual space, and an image is
By pasting (billboard image) and presenting it to the user, it is possible to prevent a sense of incongruity due to a transfer delay (download delay) of the light beam space data from the database 29. This is because the billboard image has an overwhelmingly small data volume as compared with the ray space data, and therefore the transfer time is shorter than the transfer of the ray space data.

In FIG. 11, ray space data and billboard image data are stored in external databases 29 and 31. These databases are stored in predetermined areas (27A, 27B) in the main memory 27 via a communication interface (for example, Ethernet). The drawing unit 40 draws the ray space data and billboard image data stored in the main memory in the virtual space under the control of the CPU 20.

In the first embodiment, the CPU 20 stores the ray space data from the RS data DB (database) 29 in the memory area 27A and the billboard image data from the memory area 27A.
Save to B. Whether or not the data has been stored in the memory is managed by a table as shown in FIG. 12 for each zone.

In the first embodiment, the transfer of the ray space data to the main storage memory 27 is performed according to three transfer orders. The three examples are described in the first, second and third embodiments. It will be described as.

FIG. 13 is a flowchart of a control procedure according to the first embodiment. In the first embodiment, all billboard image data are stored in steps S10 to S14.
Then, after downloading and storing the image data from the database 31 to the main memory 27B and decoding the image data, a walk-through experience in the virtual space is enabled. The features of the first embodiment are that a virtual image is presented to a user for providing a walk-through experience (steps S16 to S24), and light space data is transferred to the main storage 27A (steps S30 to S38). )
Are performed in parallel (but may be performed in series).

That is, when the billboard image transfer processing (including the decoding processing) in steps S10 to S14 is completed, the billboard image data “exists” in all the zones in the table of FIG. Will be marked.

When step S14 ends, a walk-through is enabled. That is, the viewpoint position specified by the user with the joystick or the like is detected in step S18, and in step S20, ray space data close to the viewpoint position is selected.

Here, the ray space data close to the viewpoint is defined as space data of a virtual object (including a sub virtual space) within a predetermined distance from the position of the current viewpoint in the three-dimensional space. To tell. Only the distance matters, and the user's line of sight does not matter. This is because an object in any direction is an object that the user may approach. In the example of the first embodiment, the distance may be determined in advance in relation to the size of the exhibition room.

When the ray space data corresponding to the viewpoint position does not yet exist in the memory 27, billboard image data is substituted. That is, the latter is prioritized between the billboard and the ray space image. This is because the ray space data can generate a high-definition virtual image from an arbitrary viewpoint position based on image data from a specific viewpoint position. Therefore, if the ray space data exists on the main memory 27, a virtual image is generated in step S22 in accordance with the current viewpoint position, and presented on the CRT in step S24.

In parallel with the drawing / presentation of the virtual space by the walk-through, light beam space data is transferred in steps S30 to S38. That is, step S30
Then, data transfer of one space unit of the ray space data is performed. Here, the spatial data of one space unit is, for example,
This refers to a spatial data group related to one zone or the like as shown in FIG. When the data transfer for each unit is completed, in step S34, an image is generated from the light beam space data. In step S36, the light beam space data is marked as existing in the main memory. Requests that the ray space data be sent to DB29.

In step S36, only a mark indicating that the ray space data exists is made so that the corresponding billboard image is not erased. However, from the viewpoint of effective use of the memory, as long as the ray space data exists, Unused billboard image data may be removed from main memory 27.

As described above, in the first example of the first embodiment, the billboard image is downloaded first to enable the walk-through experience in the virtual space, and thereafter, the virtual image is drawn in the virtual space. When the ray space data at the viewpoint position in real time does not exist on the main storage device, the virtual image is drawn by the billboard image data. If the required ray space data exists in the main storage device, a virtual image is drawn using the ray space data. As a result, at least a walk-through experience with billboard images,
Enable early.

FIG. 14 shows a control procedure of the second embodiment. Although the first embodiment transfers the ray space data from the DB 29 to the main memory 27A in a predetermined order, the second embodiment differs from the first embodiment in that the ray space in the space close to the current viewpoint position of the user is changed. The data is selectively transferred from the database 29. This is because the drawing closer to the user's viewpoint position should be requested.

The control procedure shown in FIG. 13 is different from the control procedure shown in FIG. 14 only in that the latter has steps S26 and S28. That is, in step S26, the current viewpoint position of the user is acquired, and in step S28,
Ray space data for one space close to the position is transferred.
Other steps are the same as in the first embodiment.

In this example, ray space data in a space close to the user's viewpoint is selected and read. However, even in one space, light beam space data of an object closest to the viewpoint is read. It is also possible.

In the second embodiment, the decoding of the beam space data is performed immediately after the transfer of the beam space data from the database. That is, the ray space data of one space unit is decoded together with the transfer and stored in the main memory. The processing that takes a long time is the transfer of the compressed ray space data and the decoding of the compressed data, except for the drawing of the virtual image. Therefore, in the third embodiment, the light space data is downloaded to the main memory at the same time as the billboard image is downloaded, and the light space data is stored in the main memory as it is. The decoding of the ray space data necessary for drawing at an arbitrary viewpoint position in real time is performed at the time when the request is generated.

FIG. 35 is a flowchart showing a control procedure according to the third embodiment. By comparing the flowchart of FIG. 35 with the flowchart of the second embodiment (FIG. 14), assuming that the same step numbers indicate the same processing, step S12 of the second embodiment is the same as that of the third embodiment. In step S13, step S20 in the second embodiment is replaced with step S21 in the third embodiment, and step S28 in the second embodiment.
Are respectively changed to step S29 in the third embodiment. That is, in step S13, downloading and decoding of billboard image data are performed in units of all spaces, and in the same step, download of ray space data is performed in units of all spaces. Then, in step S29, decoding is performed only on the ray space data in the space closest to the current user viewpoint position, and the data is used for generating a virtual image in step S34, and in step S3.
6 → displayed in step S16 →... → step S24 via step S38.

Thus, according to the third embodiment, although there is a disadvantage that the user has to wait for the download of the encoded ray space data, he can enjoy the walk-through experience in the virtual space by the billboard image at an early stage. The same effect as the first and second embodiments can be obtained. In addition, since the decoding of the ray space data is performed only on the data close to the current viewpoint position, the effect that the user can experience the virtual space at the viewpoint position in real time with good response can be obtained. Also, even if
Even if the decoding is not in time, the presentation is made at least as a billboard image, so that real-time performance is ensured.

In the third embodiment, it is described that walk-through cannot be performed until the previously coded ray space data has been read into the main memory. However, when the billboard image has been read, the walk-through and code are executed. Reading of the converted ray space data may be performed in parallel.

<Effects of the First Embodiment>
According to the embodiment,

I: By causing the billboard image data to exist in the main memory first, even when the light beam space does not exist in the DB, it is possible to eliminate the uncomfortable feeling by presenting at least a part of the image to the user. Even if it is a billboard image, the user can assume the characteristics of the virtual space or the like from the image, and if the user can determine that the image is unnecessary, the user can proceed to the next space. II: Transfer of ray space data is possible in various forms. According to the method of the first embodiment, since the transfer of the ray space data is performed in a predetermined order in parallel with the presentation of the virtual image, simultaneous processing of the walk-through and the ray space data becomes possible. I have. III: The method of the first embodiment does not always provide the data of the ray space desired by the user at the present time. However, the method of the second embodiment is to present a virtual image using image data in a space that the user actually wants. IV: According to the third embodiment, it is possible to achieve both the problem of wanting to perform a walk-through experience in a virtual space at an early stage and a walk-through experience having excellent real-time properties.

<Second Embodiment> The first embodiment is effective when the main storage capacity is enormous. However, the volume of the ray space data is enormous, and in many cases, there is no room in the system memory (main memory). The second embodiment makes it possible to draw a virtual space using ray space data with a small memory capacity. That is, the system according to the second embodiment senses a partial virtual space desired by the user, and obtains data of the partial (sub) virtual space by prefetching before entering the subspace. In the second embodiment, since the memory capacity is limited,
Once you go from one subspace to the other,
Ray space data in the previous space is deleted. On the other hand, in the pre-reading based on the estimation, if the estimated space is incorrectly identified, the ray space data secured in the memory is erroneously erased, which causes inefficiency. In this regard, the second embodiment employs a special device (described later).

FIG. 15 shows a hardware configuration of an image processing apparatus according to the second embodiment. The difference from the first embodiment is that, because the capacity of the main memory 27 is reduced, the memory area for storing the light beam space data is divided into two units of capacity (referred to as bank B1 and bank B2). It is that you are.

A feature of the second embodiment is that various information is embedded in advance in each zone of the virtual space. That is, the virtual space is in the plane direction,

An intermediate zone,

Transition zone,

Display target zone

Are divided into three types of zones.
The display target zone is a virtual zone in which the display of the virtual image based on the ray space data is set for the first purpose.
As can be seen from the example in the figure, the setting is made according to the size of the exhibition room, which is the main purpose. In the example of FIG. 16, both zone A and zone B are “display target zones”. The user can freely move inside the display target zone, and the present system generates and displays a virtual image adjusted to the user's moved viewpoint position. Outside the display target zone, there are provided a “transition zone” and a “middle zone” representing a movement route to this display target zone and another display target zone. The “transition zone” is a band-shaped zone formed with substantially the same width around the display target zone currently staying. The intermediate zone is a moving area as a “passage” formed between a plurality of display target zones.

In the example of FIG. 16, a table is used as a transition zone.
Outside the target zone A, T_AC, T _AB, T_AD, T_AEProvided
T outside the display target zone_BC, T_BA, T_BDIs set
Have been killed. For example, transition zone T_ACIs the display target zone
To control the transition between area A and display target zone C.
Information is embedded. Naturally, the transition is 2
Exist in the direction. That is, the transition to enter the display target zone
And the transition to advance (exit) from the display target zone
You.

Each zone has an attribute value indicating the attribute of the zone as shown in FIG. Furthermore, in addition to the attribute value, the zone is a display target zone (attribute value = 0).
In this case, the "necessary image ID" (hereinafter referred to as RQD-ID
Abbreviated).

The transition zone handles the transition between the two display target zones as described above. For this reason, when the viewpoint position of the user is in the transition zone, the direction of the change of the viewpoint position has one of two directions. In order to indicate a case where the transition zone transitions from the inner display target zone to another display target zone, an image of the outer display target zone is requested (that is, the image is moved to the outer display target zone). Pre-fetch request in anticipation of that)
In order to show that the
The T-DMND-ID field stores the ID of the ray space data in the display target zone to be moved. Further, in order to indicate a case where the transition zone transitions from another outer display target zone to the inner display target zone, an image of the inner display target zone is requested (that is, to the inner display target zone). In order to indicate that the image is to be moved, a “read-in request image data ID” (hereinafter abbreviated as “INT-DMND-ID”) field includes a light ray in the display target zone to be moved. The ID of the spatial data is stored. Here, “ID” is an identifier that specifies a set of one unit of light space data, as in the first embodiment.

Specifically, in the example of FIG. 16, the transition zone
Since T _AC exists between the display target zone A and the display target zone C, the transition zone T _AC may enter the transition zone T _AC for the purpose of entering the inner display target zone A. , for the purpose of advancing to the outside of the display object zone C, there is the case having entered into the transition zone T _AC, the former case, requesting the light space image data a look-ahead as INT-dMND-ID And in the latter case, EX
The light space image data C is requested in advance as the T-DMND-ID.

Outside the transition zone, in the example of FIG.
An "intermediate zone", indicated as X, is provided. The intermediate zone can be moved without performing pre-reading when moving from the display target zone to the display target zone.

The main purpose of the transition zone is to realize the look-ahead of the ray space data, which is required as the memory 27 is reduced in capacity. In addition, when the memory capacity is reduced, the buffer for storing the unnecessary ray space data must be released earlier (“first release”), but the purpose of the intermediate zone is to release the buffer first by mistake. Further, it is possible to prevent the unnecessary trouble of downloading the lost ray space data from the DB 29 again. That is, as will be described later, even if an erroneous operation of a joystick or the like is mistakenly determined to advance from the display target zone, the buffer (storage area in the memory bank) is immediately used in the second embodiment.
To the other free memory bank without releasing
The ray space data indicated by T-DMND-ID is stored. In this way, in the example of FIG. 8, even if the display returns to the display target zone, the light beam spatial data of the display target zone is stored in the memory bank, so that it is not necessary to download.

FIG. 18 shows an example of zone attribute information embedded in various zones around the display target zone A.

With reference to FIG. 19, the characteristic control of the second embodiment when the user's viewpoint position moves from the intermediate zone to the transition zone to the display target zone will be described. In the image ID embedded in the transition zone in this example, the ID (= INT-DMND-ID) of the spatial data to be subjected to prefetching when moving from the intermediate zone to the transition zone is A,
The ID (= EXT-DMND-ID) of the spatial data that is the target of the prefetching when moving from the display target zone to the transition zone is B
It is. That is, when the transition from the intermediate zone to the transition zone is performed, the INT-DMND-ID in the zone attribute information is read out, the spatial data in the subsequent display target zone is recognized as A, and the DB 29 of the spatial data is read. from (for example) to start the download to the bank B _1. Spatial data A is
Since the data includes the entire ray space data of the display target zone A, the pre-reading is effective because the light beam space can be used immediately upon actually reaching the display target zone A. Next, when moving from the transition zone to the display target zone, the RQD-
Since the ID is A, the spatial data A is stored in the memory area of the main memory 27 (for example, the bank
To ensure that it is stored in B _1). If the download has not been completed, it will wait in this display target zone.

According to FIG. 20, the user's viewpoint position moves from the display target zone to the transition zone to the intermediate zone.
That is, the characteristic control of the second embodiment in the process of moving to another display target zone will be described.

When a transition has been made from the display target zone to the transition zone, the EXT-DMND-ID in the zone attribute information is read out, and the spatial data of the display target zone adjacent to the display target zone A that has stayed up to that point is represented by B. Know that Then, downloading of the spatial data from the DB 29 is started. Since the space data A is already stored in the bank B _1, download the spatial data B is the bank B _2. That is, spatial data A in bank B ₁ represents be preserved.

In the second embodiment, while staying in the same transition zone, spatial data for a display target zone below the transition zone is held. With this retention, even if the user returns to the display target zone again, the bank B ₁
Since the spatial data A in the space can be used as it is, re-downloading of the light beam spatial data A is prevented. Also,
Since the pre-reading of the light beam space data B for the next display target zone has already started, it is expected that when the light beam space B arrives at the display target zone B, the light beam space B can be immediately drawn.

In the second embodiment, the ability to hold the ray space data of the preceding display target zone while remaining in the transition zone is limited to staying in the transition zone for a predetermined time. This time should be variable or set in advance according to the capacity of one unit of the light space, the user's preference, and the size of the virtual space, but for convenience of explanation, in this second embodiment, For example, it is set to 5 seconds. That is, in the example of FIG. 21, after shifting from the display target zone A to the transition zone, returning to the display target zone, shifting to the transition zone again, and returning to the display target zone,
Further, the operation of shifting to the transition zone is performed. In this operation, the ray space data A is held because each time staying in the transition zone was less than 5 seconds. is there.

On the other hand, in the example of FIG.
Since was limited seconds, despite staying in the transition zone, the data A of the bank B ₁ represents purged (disabled), the buffer will have been released.

While the user's viewpoint position remains in the transition zone as shown in FIG. 21, the user operates the mouse or the joystick to move the inside of the display target zone, but moves the peripheral portion thereof. This is because if performed, the user may erroneously enter the transition zone, resulting in erroneous recognition for the user.
However, staying in the transition zone for more than 5 seconds means that
Since it can be inferred that the user intends to leave the lower display target zone, the ray space data of the zone stored in the buffer may be discarded.

Next, a control procedure according to the second embodiment will be described with reference to flowcharts and the like. The 23rd
FIG. 26 to FIG. 26 explain various registers used in this control procedure. The actual control procedure is shown in FIG. 27 and subsequent figures.

FIG. 27 shows a main routine of a control procedure according to the second embodiment.

That is, the billboard image is downloaded from the billboard image DB 31 in step S100. In the second embodiment, in a display target zone such as an exhibition room, a virtual image based on ray space data is displayed in principle, but as described above, the bank capacity for storing the ray space of the main memory is limited. Since the number is small, the light beam space data is pre-read each time it approaches the display target zone. For this,
In some cases, the ray space data may not be available when the user enters the display target zone. In such a case, the billboard image is displayed as a substitute image.

[0087] All of the billboard image in step S100 is if it is downloaded to the bank _{B 3} region of the memory 27, step S102 in the following, the user walkthrough allowed.

In step S102, it is determined whether the user has operated the joystick or the like to move the virtual viewpoint position. If there is a movement of the viewpoint position, it is determined in step S104 whether the movement is beyond the zone. If the movement is not across zones, the process proceeds to step S116, where a virtual image at the viewpoint position is generated and displayed. In this case, if there is no ray space data, a billboard image is displayed. If there is ray space data, the ray space data is converted into a virtual image and displayed. FIG. 28 shows a case where a virtual image based on ray space data is displayed and a case where a billboard image is displayed, corresponding to the viewpoint position.
It should be noted that the billboard image is the same as the first embodiment and the second embodiment.
In the embodiment, VRML (Virtual Reality Modeling Lang
uage). The advantage of displaying a billboard image is that when a user walks through a virtual space, so-called browsing of a target sub-space is often performed. In such a case, a high-definition image based on ray space data is used. This is because the purpose is sufficiently achieved by the billboard image.

If the zone has been changed due to the user's movement of the viewpoint position, the flow advances to step S104, and in step S106, the attribute value of the display target zone stored in the register CR-Z (see FIG. 21) is read. , Save to register PR-Z. In step S108, zone attribute information (FIG. 17) of the zone is read, and the attribute value is registered in the register.
Hold in CR-Z. In step S112, the register PR-Z
The zone change is detected by comparing the attribute value of the previous zone with the attribute value of the current zone in the register CR-Z.
Here, the zone change can be recognized as a change in the attribute value,
In the second embodiment,

2 → 1 (intermediate zone → transition zone),

1 → 0 (transition zone → display target zone)

0 → 1 (display target zone → transition zone)

1 → 2 (transition zone → intermediate zone)

There are four possible changes. Therefore, in step S114, processing corresponding to these changes is performed.

<Intermediate Zone → Transition Zone> When the user moves from the intermediate zone to the transition zone, it is often expected that the user will further move from this transition zone to the display target zone. On the other hand, in the second embodiment, as described later, the ray space data of the display target zone, which is the target of the user's desired experience, is changed to the transition zone following the previous display target zone (0 → in FIG. 31). It should have read ahead in 1 move). Therefore, in step S200, the light space data with INT-DMND-ID is attribute information of the transition zone, the memory bank B ₁ or B _2, checks whether stored on either side. This check is performed by selecting one of the registers F _B1 and F _B2 having a value of 1 (the data in the bank is valid), and selecting the bank B _X having a value of 1
Can be checked from the value of the register ID _BX corresponding to the memory bank in which the beam space data is stored. If the ray space has already been downloaded into the bank, return from the control procedure of FIG. 29 and return to the main routine.

If the ray space data has not been downloaded, it is determined in step S202 whether the data is currently being downloaded. This determination is made by the register COM managing the state of the communication interface 24 (FIG. 15)
26 (see FIG. 26). CO
If M = 1, it is determined that the ray space data is currently being downloaded to one of the banks, and the process returns to the main routine. In step S202, there is no need to wait for the end of the download. This is because the download may have been completed before moving from the transition zone to the next display target zone. It should be noted that whether or not this download is in progress is determined by the flag F _{B1
Alternatively} , it is better to confirm by determining whether the value of _FB2 is 3.

If not downloaded, download (prefetch) is performed from the database DB 29 in step S204 and subsequent steps. That is, in step S204,
Find an empty memory bank. Empty memory bank, the value of the register F _B (Figure 23) is a memory bank is zero.
If such a bank is found, the bank number is stored in the work register WK (= 0 or 1). In step S206, the value of the flag F _WK of the bank B _WK is set to a value 3 indicating that downloading is in progress. Then, in step S208, a transfer request for download is issued to the ray space DB 29. Then, the value of the register of the communication interface 24 is set to COM = 1 so as to indicate that it is download.

Thus, when the vehicle enters the transition zone from the intermediate zone, the storage state of the ray space data of the display target zone, which will enter further, is checked. If it is not stored, download is performed. Start prefetching of ray space data.

If NO is determined in step S200 (the necessary ray space data does not exist in the memory bank), it is determined in step S202 whether or not the data is being downloaded. Regardless of the judgment result, the control procedure of FIG.
16, but in step S116, since the virtual image is drawn using the spatial data at the moved viewpoint position, if ray space data exists, the drawing using the ray space data has been completed. If not, an alternative display using a billboard image is performed.

<Transition Zone → Display Target Zone> FIG. 30 shows a control procedure in the case where the transition from the transition zone to the display target zone is performed. The transition from the transition zone to the display target zone is performed in addition to the normal movement from the intermediate zone to the transition zone to the display target zone, as well as from the display zone to the transition zone as shown in FIG. This includes the case of returning to the display target zone. In any case,
Either the necessary spatial data already exists in the memory bank or it is being downloaded into that memory bank. Step S250
If the determination in step 2 is NO, the control ends because there is an error. This determination is made by searching the table of FIG. 24 with reference to the value corresponding to the required image ID (RQD-ID) of the attribute information (FIG. 17) of the display target zone. That is, when entering the display target zone A, if B _A = 1, the ray space data A is in the bank B ₁ , and if B _A = 2, the ray space data A is in the bank B _1.
It is stored in the B _2.

On the other hand, YES in step S250, that is,
If the necessary beam space data already exists in the memory bank, or if the data is being downloaded, it is checked in step S252 whether the value of the timer TMR is zero. That is, in the movement from the display target zone to the transition zone, as described above, the timer TMR is activated for 5 seconds. Therefore, when returning to the display target zone, the timer TMR needs to be reset. . Therefore, in step S252, it is determined whether the 5-second monitoring timer TMR has been activated.
Reset at 254.

In steps S256 and S258, the ray space data once marked "gray" is restored as "valid" data. Regarding the processing of step S256 and step S258, the third
This will be performed in connection with the description of step S290 and subsequent steps in FIG.

Thus, in the display target zone, the user can experience a virtual space based on ray space data.

<End of Download> The end of download is interrupted by the operating system in this control procedure. When this interrupt is detected,
The control procedure of FIG. 34 is started.

At step S400 in FIG. 34, the state of the communication interface 24 is set to the idle state (COM = 0). In step S402, the memory bank in which data has been stored by the download is checked. That is, look for the bank is F _B = 3, retreats the bank number in the work register WK. In step S404, the value of the register _FWK of the bank is set to "1" to indicate that the data is valid. Further, step S40
In step 6, in order to identify the data stored in the bank B _WK , the value of the ID _WK is used as the identifier (A, B, C) of the ray space data.
…). Further, in step S408, a value indicating the identifier of the downloaded light beam space data is set in the register B (FIG. 24) indicating the storage destination of the space data.

Thus, the registers F _B1 , F _B2 , ID _B1 , I
By using D _B2 , B _A, etc., it is possible to arbitrarily check the location of the bank in which the ray space data is effectively stored.

<Display target zone → transition zone> The control procedure when moving from the display target zone to the transition zone is the third control procedure.
It is shown in FIG.

That is, in step S280, the timer TMR
Start Whether or not the timer TMR times out (the value of TMR reaches a predetermined value) is monitored by the control procedure of FIG.

In step S282 and subsequent steps, preparation is made for downloading the ray space data for the next display target zone (adjacent display target zone). That is, step S282
In, in order to find an empty memory banks, locate the bank value of the register F _B is 0, and stores the bank numbers in the work register WK. In step S284, the memory bank B _WK is marked as being downloaded (F _WK = 3). Then, in step S282, the start of download is instructed to the interface 24. In step S288, the status of the interface 24 is marked as being downloaded (COM =
3) Yes.

Further, in step S290 and subsequent steps, the ray space data used for the drawing purpose in the previous display target zone (the display target zone where the user has stayed until then) is marked as “gray”. As described above, when moving from the display target zone to the transition zone, there is a high possibility of moving to another display target zone, so the ray space data used in the previous display target zone may be unnecessary High in nature. However, in the second embodiment, the ray space data is held in consideration of the joystick erroneous operation, as described with reference to FIGS. 21 and 22. The ray space data held in the memory bank is referred to in this embodiment as being in a "gray" state because it may be erased. The erasure of the ray space data in the “gray” state is performed in step S302 in FIG. 32, which is a control procedure for 1 → 2 movement.

In step S290, the transition zone
From the value of the INT-DMND-ID, the identifier of the ray space data used for the previous display target zone is known, and this value is stored in the work register WK. In step S292, the register B holding the storage destination of the image is stored. Referring to (FIG. 24), the number of the memory bank in which the beam space data is stored is known, and the value is stored in the work register WK. Then, in step S294, F _WK = 2 to mark the state of this memory bank as “gray”.

Thus, in the control procedure of FIG. 31, the pre-reading of the ray space data for the next display target zone is started, and the ray space data used so far is set to the “gray” state. It can be resurrected at any time.

If the user performs an operation to return to the original display target zone again, the operation is detected as a transition from the transition zone to the display target zone, and the third operation is performed.
The processing is performed by step S256 in FIG. That is, in step S256, a bank in the gray state is searched, and in step S258, the state value is set to F _B = 1.

[0114] In step S286, the download has started, so that the light space data for the next display target zone is marked valid (F _B = 1) on the bank in due course, i.e., effective image Although a state occurs in which data is stored in both of the two memory banks (B1 and B2), in the second embodiment, since image drawing is performed in accordance with the value of the register B in FIG. Ray space data is not confused.

<Transition Zone → Intermediate Zone> When the vehicle moves from the transition zone to the intermediate zone, the control procedure shown in FIG. 32 is executed.

That is, in step S300, in order to purge the ray space data in the gray state, a bank storing the ray space data is searched. That is, in step S300, the bank where F _B = 2 is checked, the bank number is stored in the work register WK, and the status value of the register F _WK of the bank is set to 0 indicating that the data is invalid. Further, in step S304, the values of the corresponding register ID _B (FIG. 23) and register B (FIG. 24) are reset so that the invalidation of the data is reflected.

<Generation of Timeout> The control procedure when the 5-second timer TMR times out will be described with reference to FIG. This timer TMR is effective only when the user's viewpoint position is within the transition zone.

In step S500, the timer TMR is reset. In step S502, a bank for storing the ray space data in the "gray" state is searched for, and the bank number is stored in the work register WK. Step S
At 504, the value of the status register _FWK of the bank of that number is set to 0 (data invalid). In step S506, the values of the related register ID _B (FIG. 23) and register B (FIG. 24) are reset so that the invalidation of the data is reflected.

Thus, when the user stays in the transition zone for a predetermined time or more, it is assumed that the user's intention to leave the original display target zone is clear, and the ray space data in the gray state is invalidated. That is, the buffer is automatically released on behalf of the user.

The second embodiment can be variously modified.

I: For example, in the second embodiment, the zone surrounding one display target zone is provided with a double zone, that is, only two transition zones and an intermediate zone. It is not limited to one. For example, it is proposed to provide two upper transition zones and two lower transition zones. That is, in the second embodiment, the pre-reading of the ray space data is performed when proceeding to the next display target zone (moving from the display target zone to the transition zone). However, the look-ahead was also performed when proceeding from the intermediate zone to the display target zone, but since this is a look-ahead that starts in the transition zone of the next layer of the display target zone, the display target is immediately displayed from the transition zone It will be shifted to the zone and its effectiveness will be poor. Therefore, as described above, a two-layer transition zone is provided, and in the upper transition zone, pre-reading when entering the display target zone is performed, and in the lower transition zone, another display target zone is displayed from the display target zone. Read ahead when proceeding to. In this case, the intermediate zone becomes unnecessary. II: In the second embodiment, for example, the display target zone
(A) → transition zone from A to B → intermediate zone → transition zone of C → if the display zone is moved to C, ray space data for display zone B in the transition zone from A to B Is performed, but after all, since it has moved to the display target zone C, the prefetching is not an efficient prefetching. In preparation for such a case, by dividing all the intermediate zones in correspondence with the display target zones, it is possible to prevent inefficiency of the prefetching.

III: In the above embodiment, ray space data has been described as an example, but the present invention is not limited to this.
The present invention is also applicable to spatial data that requires a certain amount of time for data transfer, that is, any spatial data that requires a data transfer time that hinders real-time processing. Therefore, according to the present invention, between the main memory and the DB,
The present invention is not applied only to a system connected by a communication line, and it should be determined whether or not the processing of the present invention is necessary based on the degree of demand for real-time properties of the application. Therefore, in some cases, the present invention is also applicable to a system in which the main storage and the database DB are connected by a parallel bus.

IV: In the above-described second embodiment, the ray space data in the gray area is erased if it stays in the transition zone for a predetermined time. (Or, for example, 36th
The operation may be modified so that the erasing operation is started by an operation on a predetermined icon as shown in the figure. V: In the second embodiment, the ray space data is encoded in the database 29 and is decoded every time it is downloaded from the database. However, as described in connection with the third example of the first embodiment, while decoding of encoded spatial data requires time, encoded spatial data does not occupy a large memory capacity. That is, depending on the memory capacity of the main memory provided in the system, there is a possibility that there is room for storing all of the encoded light beam space data. Therefore, if there is room in the main memory 27, a modification similar to that of the third embodiment is performed on the second embodiment, that is, all of the ray space data is downloaded to the memory 27, We propose a modification that decodes only the ray space data at the user viewpoint position that has moved in real time. In this modified example, a processor or task dedicated to the decoding process is separately provided from the second embodiment, and the download operation of the second embodiment is modified so as to correspond to the decoding process. That is, whether or not downloading of flags (COM) is changed to whether flag or during the decoding process, the data in the bank is effective whether the flag (F _B of FIG. 23) is decoded It is a flag indicating whether or not there is. Then, in a modification, the ray space data of all display target zones is downloaded together with billboard image data in step S100 (FIG. 27). Then, the look-ahead from the database of the ray space data when entering the new display target zone is changed to an operation of prioritizing the process of decoding the encoded data.

With such a modification, the real-time processing is further improved compared to the second embodiment.

[0125]

As described above, according to the present invention, the range of the spatial data to be downloaded or the range of the spatial data to be decoded is limited to a predetermined range from the viewpoint position. And the time required for decoding can be reduced, and as a result, space rendering with real-time property can be realized.

[Brief description of the drawings]

FIG. 1 is a view for explaining the principle of generating ray space data.

FIG. 2 is a diagram illustrating data in a real space.

FIG. 3 is a diagram when the space in FIG. 2 is represented by ray space data;

FIG. 4 is a view for explaining the principle of generating real space data when there are a plurality of cameras.

FIG. 5 is a view for explaining the principle of generating ray space data when there are a plurality of cameras.

FIG. 6 is a diagram showing ray space data when there are a plurality of cameras,
FIG. 7 is a diagram for explaining the principle of generating ray space data (x + Zu = X) at an arbitrary viewpoint position.

FIG. 7 is a view for explaining the principle of reconstructing a real space from an arbitrary viewpoint in FIG. 6;

FIG. 8 is a diagram illustrating a problem that may occur in a walk-through environment proposed by the inventor.

FIG. 9 is a diagram illustrating a configuration of a virtual space presentation device (virtual image drawing device) according to the first embodiment and the second embodiment.

FIG. 10 is a view for explaining the configuration of a virtual space in the first embodiment and the second embodiment.

FIG. 11 is a diagram illustrating a configuration of a main part in the device according to the first embodiment.

FIG. 12 is a view for explaining a configuration of a table for managing download states of ray space theory data and billboard image data in the system of the first embodiment.

FIG. 13 is a flowchart illustrating a control procedure according to a first example of the first embodiment.

FIG. 14 is a flowchart illustrating a control procedure according to a second example of the first embodiment.

FIG. 15 is a block diagram illustrating a configuration according to a second embodiment of the present invention.

FIG. 16 is a view for explaining a configuration example of a virtual space used in the second embodiment.

FIG. 17 is a diagram showing attribute information given to each zone in the virtual space in the second embodiment.

FIG. 18 shows zone A of FIG. 16 according to the attribute of FIG.
FIG. 6 is a diagram for explaining attribute values given to the user.

FIG. 19 is a diagram schematically illustrating a main control operation performed in a process in which a user's viewpoint position moves from an intermediate zone to a transition zone and further to a display target zone in the second embodiment.

FIG. 20 is a diagram schematically illustrating a main control operation performed in a process in which a user's viewpoint position moves from a display target zone to a transition zone and further to an intermediate zone in the second embodiment.

FIG. 21 is a diagram schematically illustrating a control operation when a user's viewpoint position reciprocates between a display target zone and a transition zone in the second embodiment.

FIG. 22 is a diagram schematically illustrating a control operation when the user's viewpoint position remains in the transition zone in the second embodiment.

FIG. 23 is a view for explaining various registers used in the control procedure of the second embodiment, in particular, a register for managing a state of a memory bank and a register for storing identification of an image stored in the bank.

FIG. 24 is a view for explaining various registers used in the control procedure of the second embodiment, particularly registers for managing the relationship between theoretical ray space data to be drawn in each display target zone and the storage destination of the data; .

FIG. 25 shows various registers used in the control procedure of the second embodiment, in particular, a register PR-Z storing the identification of the display target zone immediately before the user and a register CR storing the identification of the current display target zone. The figure explaining -Z.

FIG. 26 is a diagram illustrating a register COM and a timer TMR used in a control procedure according to the second embodiment.

FIG. 27 is a flowchart according to a main routine of a control procedure according to the second embodiment.

FIG. 28 is a diagram illustrating a relationship between a virtual image based on ray space theory data and a virtual image based on billboard image data in the second embodiment (the same applies to the first embodiment).

FIG. 29 is a flowchart illustrating a part of a control procedure according to the second embodiment;

FIG. 30 is a flowchart illustrating a part of a control procedure according to the second embodiment.

FIG. 31 is a flowchart illustrating a part of a control procedure according to the second embodiment.

FIG. 32 is a flowchart illustrating a part of a control procedure according to the second embodiment.

FIG. 33 is a flowchart illustrating a part of a control procedure according to the second embodiment;

FIG. 34 is a flowchart illustrating a part of a control procedure according to the second embodiment.

FIG. 35 is a flowchart illustrating a part of a control procedure according to a third example of the first embodiment.

FIG. 36 is an exemplary view for explaining the shape of an icon according to a modification of the second embodiment;

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Daisuke Kotake 6-145 Hanasakicho, Nishi-ku, Yokohama-shi Yokohama Hanasaki Building M-R System Co., Ltd. Research Institute F-term (reference) 5B050 BA09 BA10 CA05 EA10 EA27 EA28 FA02 FA09 5C061 AA29 AB01 AB08 AB21 AB24

Claims (33)

[Claims] 1. A space drawing method for drawing a virtual space viewed from an arbitrary viewpoint position, wherein space data of a first format of a virtual object in the virtual space is stored in a first space.
The present viewpoint position is detected. If the spatial data of the virtual object within a predetermined range from the detected current viewpoint position does not exist in the second memory, the spatial data is stored in the first memory. And drawing the virtual space on the basis of the downloaded space data in the second memory. 2. The method according to claim 1, further comprising: storing in advance in the second memory spatial data of a virtual object in the virtual space as spatial data of a second format different from the first format; While data is being downloaded from the first memory to the second memory, the second
The space drawing method according to claim 1, wherein the virtual space is drawn based on the space data of the second format in the memory of (1). 3. The space according to claim 2, wherein the spatial data in the first format is spatial data based on a real image, and the spatial data in the second format is billboard image data. Drawing method. 4. When the current viewpoint position is separated from the viewpoint position corresponding to the spatial data already stored in the second memory by a predetermined distance or more, the stored spatial data is replaced with the second spatial data. 4. The space drawing method according to claim 1, wherein the space drawing method is released from the memory. 5. The first memory is an external memory,
5. The space drawing method according to claim 1, wherein the second memory is a main storage memory. 6. The billboard image data is stored in the first memory in advance, and the billboard image data in the first memory is stored in the second memory before drawing the virtual space. The space drawing method according to claim 3, wherein the space drawing is performed. 7. The space drawing method according to claim 1, wherein a virtual walk-through environment is provided to a user in the virtual space. 8. A space drawing method for drawing a virtual space viewed from an arbitrary viewpoint position, wherein the space data of the first format of the virtual object in the virtual space is compressed and stored in an internal memory, and the current viewpoint position is In the internal memory, if there is compressed spatial data of a virtual object within a predetermined range from the detected current viewpoint position, but there is no decoded spatial data, the compressed spatial data And drawing a virtual space based on the decoded space data. 9. The compressed spatial data of the first format, wherein spatial data of a virtual object in the virtual space is stored in advance in the internal memory as spatial data of a second format different from the first format. 9. The space drawing method according to claim 8, wherein a virtual space is drawn based on the space data in the second format while decoding is performed. 10. The space according to claim 9, wherein the spatial data in the first format is spatial data based on a real image, and the spatial data in the second format is billboard image data. Drawing method. 11. When the current viewpoint position is separated from a viewpoint position corresponding to decoding space data already stored in the internal memory by a predetermined distance or more, the decoding space data is released from the internal memory. The space drawing method according to any one of claims 8 to 10, wherein: 12. The compressed space data stored in an external memory outside of the internal memory in advance, and the compressed space data in the external memory is downloaded to the internal memory. The space drawing method according to any one of the above. 13. The billboard image data is stored in advance in an external memory outside the internal memory, and the billboard image data in the external memory is downloaded to the internal memory in advance before drawing a virtual space. The space drawing method according to claim 10, wherein: 14. A virtual walk-through environment for a user in the virtual space.
13. The space drawing method according to any one of claims 12 to 12. 15. A storage medium for storing a computer program for realizing the space drawing method according to claim 1. Description: 16. A virtual space drawing apparatus for drawing a virtual space viewed from an arbitrary viewpoint position, comprising: a first memory for storing space data in a first format of a virtual object in the virtual space; Means for detecting, when the spatial data of the virtual object within a predetermined range from the detected current viewpoint position does not exist in the second memory, downloads the spatial data from the first memory to the second memory And a drawing means for drawing a virtual space based on the downloaded space data in the second memory. 17. The method according to claim 17, further comprising: storing in advance the spatial data of the virtual object in the virtual space in the second memory as spatial data of a second format different from the first format; Data from the first memory to the second memory
17. The virtual space drawing apparatus according to claim 16, wherein the virtual space is drawn based on the space data of the second format in the second memory while downloading the data to the memory. 18. The virtual system according to claim 17, wherein the first format spatial data is spatial data based on a real image, and the second format spatial data is billboard image data. Spatial drawing device. 19. When the current viewpoint position is separated from the viewpoint position corresponding to the spatial data already stored in the second memory by a predetermined distance or more, the stored spatial data is stored in the second memory. 19. The virtual space rendering apparatus according to claim 16, wherein the virtual space rendering apparatus is released from the memory. 20. The virtual space drawing apparatus according to claim 16, wherein the first memory is an external memory, and the second memory is a main storage memory. 21. Billboard image data is stored in said first memory in advance, and billboard image data in said first memory is stored in said second memory in advance prior to rendering of a virtual space. 19. The virtual space drawing device according to claim 18, wherein the device is downloaded. 22. A virtual walk-through environment for a user in the virtual space.
22. The virtual space drawing apparatus according to any one of 6 to 21. 23. A virtual space drawing apparatus which draws a virtual space viewed from an arbitrary viewpoint position, wherein space data of a first format of a virtual object in the virtual space is compressed and stored in an internal memory, The position is detected.In the internal memory, if there is compressed space data of the virtual object within a predetermined range from the detected current viewpoint position, but there is no decoded space data, the compressed space A virtual space drawing apparatus, which decodes data and draws a virtual space based on the decoded space data. 24. The compressed spatial data of the first format, wherein spatial data of a virtual object in the virtual space is stored in advance in the internal memory as spatial data of a second format different from the first format. 24. The virtual space drawing apparatus according to claim 23, wherein a virtual space is drawn based on the space data in the second format while decoding is performed. 25. The virtual system according to claim 24, wherein the spatial data in the first format is spatial data based on a real image, and the spatial data in the second format is billboard image data. Spatial drawing device. 26. When the current viewpoint position is separated from the viewpoint position corresponding to the decoding space data already stored in the internal memory by a predetermined distance or more, the decoding space data is released from the internal memory. The virtual space drawing apparatus according to any one of claims 23 to 25, wherein: 27. The method according to claim 23, wherein compressed space data is stored in an external memory outside the internal memory in advance, and the compressed space data in the external memory is downloaded to the internal memory. A virtual space drawing apparatus according to any one of the above. 28. Billboard image data is stored in an external memory outside of the internal memory in advance, and billboard image data in the external memory is downloaded to the internal memory in advance of drawing a virtual space. 26. The virtual space drawing apparatus according to claim 25, wherein: 29. A virtual walk-through environment is provided to a user in the virtual space.
28. The virtual space drawing apparatus according to any one of 3 to 27. 30. The space drawing method according to claim 1, wherein the predetermined range indicates a virtual object within a range of a predetermined distance from the detected current viewpoint position. 31. The detected virtual object within a predetermined range from the current viewpoint position includes a virtual object in a sub-virtual space within the predetermined range from the current viewpoint position. 31. The space drawing method according to any one of 14 and 30, wherein 32. The virtual space drawing apparatus according to claim 16, wherein the predetermined range indicates a virtual object within a predetermined distance from the detected current viewpoint position. . 33. The detected virtual object within a predetermined range from the current viewpoint position includes a virtual object in a sub-virtual space within the predetermined range from the current viewpoint position. 33. The virtual space drawing apparatus according to any one of 29 and 32.