JPH0563879A - Cg data transmission system - Google Patents

Abstract

PURPOSE:To make a storage device of picture data in a center station small and to reduce the cost by generating CG models transferred to a terminal equipment in the arrangement order based on sets of view points and noticed point coordinates, revising and displaying the models. CONSTITUTION:When the user of a terminal equipment gives a display request of a menu pattern of computer graphics(CG) data stored in a center station, the center station receiving the transfer request retrieves a CG data file to be stored and sends it to the terminal equipment in a prescribed data format. Data representing total number of polygons are arranged in the data format and data representing number of apexes of each polygon and coordinates of each apex are arranged succeedingly by total number of polygons and sets of view point coordinates and noticed point coordinates designating the direction of observation are arranged by plural directions. The terminal equipment processes the CG models included in the received CG data based on the sets of the view points and noticed point coordinates in the order of the arrangement and the display data are generated and revised.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CG data transmission system used as a videotex system such as a captain system.

[0002]

2. Description of the Related Art A videotex system such as a captain system stores a large number of still images in a center station, and a still image requested by an arbitrary terminal device connected to the center station via a data communication network is stored. The center station sends it to this terminal device and displays it on the monitor.

[0003]

Assuming a photograph of a passenger car as an example of still images stored in the center station,
It is necessary to store a large amount of image data such as a front view photo, a diagonal front view photo, and a lateral view photo, which makes the storage device large and expensive, and also increases the installation space. There is a problem.

Further, in the case of the above-mentioned passenger car, since a corresponding still image must be transmitted every time the viewing direction is changed,
There is a problem in that it takes a long time to transmit the data, and not only the time is extended from the time when the request is sent to the center station until the display on the terminal device is completed, but also the data communication network is burdened with the transmission amount.

[0005]

According to the CG data transmission system of the present invention, the center station accumulates CG data including a CG model and an array of pairs of viewpoint and gazing point coordinates, and responds to the request of the terminal device. It is provided with a means for sending. On the other hand, when the terminal device receives the CG data from the center station, the terminal device processes the CG model included in the CG model in the order of arrangement based on the set of the viewpoint and the gazing point coordinates, thereby creating or updating the display data and displaying it. Is equipped with.

[0006]

That is, according to the present invention, as is known in the field of computer graphics (CG), the basic form of a passenger car or the like is specified by a CG model such as a polygon or a function, and a plurality of observation directions corresponding to this are specified. Is specified by an array of a set of viewpoint and gazing point coordinates, and this is sent as CG data from the center station to the terminal device. This CG
The terminal device that receives the data sequentially displays the image data viewed from a plurality of observation directions by creating and updating the CG model in the order of arrangement based on the set of the viewpoint and the gazing point coordinates. As a result, the amount of image data stored in the center station is reduced. This is because the second and subsequent display data are substantially compressed to the data amount of the second and subsequent viewpoint and gazing point coordinate sets. This data compression reduces the size and cost of the storage device and saves the installation space. Further, since the amount of data to be transmitted is also reduced, the burden on the amount of data transmitted in the data communication network is reduced, and the time required for transmission is shortened, and the time required for updating the display screen is shortened.

[0007]

FIG. 2 is a block diagram showing an example of the configuration of a terminal device in a CG data transmission system according to an embodiment of the present invention. 1 is a CPU, 2 is a control ROM, and 3 is a control RA.
M, 4 is a storage ROM, 5 is a character font ROM, 6 is a sync signal generation circuit, 7 is a code surface / pattern surface display control unit, 8 is a code surface display memory, 9 is a pattern surface display memory, and 10 is a natural image. A display control unit, 11 is a natural image display memory, 12 is a natural image expansion processing unit, 13 is a display combining unit, and 14 is a display combining unit.
Is a D / A converter, 15 is a monitor, 16 is a printer, 1
Reference numeral 7 is a melody voice output unit, 18 is a speaker, 19 is an input interface unit, 21 is a remote controller, 21 is a line interface unit, 22 is a system bus, 23 is a data communication line, and 24 is a CG rendering unit. That is, the terminal device of this CG data transmission system has almost the same configuration as the captain terminal except for the CG rendering unit 24.

The terminal device shown in FIG. 2 is connected to a center station via a data communication line 23 and a data communication network (not shown). The remote controller 20 requests the user of this terminal device to display the menu screen of the CG data stored in the center station.
When it is issued by the operation of, the CPU 1 that has received the display request via the input interface unit 19 sends a menu screen transfer request to the center station via the line interface unit 21. The code format menu screen transferred from the center station that has received this transfer request is CR via the code surface / pattern surface display control unit 7, the code surface display menu 8, the display combining unit 13 and the D / A conversion unit 14.
It is displayed on the monitor 15 such as T. When the user of this terminal device selects desired CG data by referring to the displayed menu screen and inputs the identification number by operating the remote controller 20, the CPU 1 accepting the identification number receives the identification number via the line interface section 21. A CG data transfer request is sent to the station.

The center station that has received this CG data transfer request retrieves the CG data file that is being stored and sends it to the terminal device in the data format as shown in FIG. This data format conforms to that of the Captain System, and at the beginning is a 1-byte DI (Data Identifier) that indicates that the transmission data is data of the transparent mode coding system (T), followed by the transmission data. 1-byte OP (Operatio Code) that indicates that is CG data, and C such as polygons and functions
A 1-byte format 1 indicating the type of G model and the presence / absence of animation is arranged in order. Then, in the CG data display area on the monitor 15, (X, Y)
After the coordinates and size (dX, dY), the shading No. that specifies the shading method, the number of light sources, the data that specifies the coordinates and direction of each light source are arranged, the CG model is arranged.

The data format of FIG. 1 exemplifies the case where the CG model is a polygon. First, data indicating the total number of polygons is arranged, and subsequently, the number of vertices of each polygon and (X, Y of each vertex are arranged. , Z) data indicating the coordinates are arranged for the total number of polygons. Subsequent to this CG model, sets of viewpoint coordinates and gazing point coordinates that specify the direction of observation are arranged for a plurality of directions.

When the CPU 1 receives the CG data in the data format shown in FIG. 1 through the line interface unit 21, the (X, Y) coordinates and size (d) of the CG data display area.
X, dY), these are transferred to the natural image display control unit 10 and the shading No. The following CG data is transferred to the CG rendering unit 24. The CG rendering unit 24 that has received this CG data calculates the coordinates of each vertex of each polygon using the one arranged at the beginning of the set of viewpoint coordinates and the gazing point coordinates that specify the direction of observation. A polygonal figure that connects the two is created and transferred to the natural image display control unit 10. The natural image display control unit 10 writes the polygonal figure received from the CG rendering unit 24 in the storage area of the natural image memory 11, and periodically reads it from this storage area to display the polygonal figure.
The data is displayed in the data display area on the monitor 15 designated by the coordinates and the size by being transferred to.

The entire surface of the monitor 15 may be assigned as the display area of the CG data, but typically,
As illustrated in FIG. 2, the entire display area is a display area (A) of CG data such as a photograph of a passenger car, and the performance of this passenger car,
It is divided into a display area (B) for explaining the size and price. This description is sent from the center station to the transmission line in the form of a code separately from the CG data, transferred to the code / pattern surface display control unit 7 via the line interface unit 21 and the CPU 1, and is transmitted to the code surface display memory. 8 is written in. This description is periodically read from the code surface display memory 8, and is superimposed on the CPU data in the display synthesizing unit 13 and displayed on the monitor 15.

The CG rendering unit 24 creates a first polygonal figure and transfers it to the natural image display control unit 10, and when a predetermined time has passed, a set of viewpoint coordinates and gazing point coordinates for designating the direction of observation. The coordinates of the vertices of each polygon are calculated using the second array, and a polygonal figure connecting them is created and transferred to the natural image display control unit 10. The natural image display control unit 10 uses the CG rendering unit 24 to display the display data held in the natural image memory 11.
The display data on the monitor 15 is updated by updating it with new display data received from the storage area and periodically reading it from this storage area and transferring it to the display combining section 13.
The updated display data may be, for example, a photograph of the passenger car seen from the front diagonally, not from the front.

As described above, the CG rendering unit 24
New display data is created in a predetermined cycle by processing the CG model in the order of arrangement based on the set of viewpoint and gazing point coordinates, and transferred to the natural image display control unit 10. The natural image display control unit 10 updates the display data held in the natural image display memory 11 with the latest display data received from the CG rendering unit 10, so that the display data on the monitor 15 becomes like an animation. It is changed in a predetermined cycle. As a result, the user can successively feel the appearance of the desired passenger car as seen from the front, the appearance as seen from the left diagonal front, the appearance as seen from the right front, and so on.

When the user wants to stop updating the CG data on the monitor, he operates the remote controller 20 to issue a stop command. This stop command is transferred to the CG rendering unit 24 via the input interface unit 19 and the CPU 1, and the CG rendering unit 24 receiving this command creates new display data based on the next set of viewpoint and gazing point coordinates. Stop. As a result, the display data just before the update is continuously displayed on the monitor. The cancellation of the stop of the update of the display data is performed by a command from the remote controller 20.

The configuration in which the display screen is updated with the CG data at a predetermined cycle has been described above. However, it is also possible to adopt a configuration in which the display screen is updated at a constant cycle designated by the user, or it is possible to wait for a command from the user.

[0017]

As described in detail above, the C of the present invention
According to the G data transmission system, the CG model transferred from the center station to the terminal device in response to a request is created and updated in the order of arrangement based on the set of viewpoint and gazing point coordinates. Since the configuration is such that the viewed image data is sequentially displayed, the second and subsequent display data are substantially compressed to the data amount of the second and subsequent viewpoint and gazing point coordinate groups. As a result, it is possible to reduce the size and cost of the image data storage device in the center station and to reduce the installation space.

Further, since the amount of data to be transmitted is also reduced, the burden on the amount of data transmission of the data communication network is reduced, and the time required for transmission is shortened, and the update time of the display screen is also shortened. It

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an example of a data format of CG data sent from a center station to a terminal device in a CG data transmission system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a terminal device of a CG data transmission system according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram showing an example of display data displayed on the monitor of the terminal device in the CG data transmission system of the embodiment of the present invention.

[Explanation of symbols]

 1 CPU 10 Natural Image Display Control Unit 11 Natural Image Display Memory 13 Display Synthesis Unit 15 Monitor 21 Line Control Unit 23 Data Communication Line 24 CG Rendering Unit

Claims (2)

[Claims] 1. A center station that stores image data,
An image data transmission system comprising a plurality of terminal devices connected to this center station via a data communication network, and transmitting image data from the center station to this terminal device for display in response to a request from any terminal device. The center station includes means for accumulating CG data including a CG model and an array of pairs of viewpoints and gazing point coordinates, and transmitting the CG data in response to a request from the terminal device. When the CG data is received from the CG model, the CG model included in the CG model is processed in the order of arrangement based on the set of the viewpoint and the gazing point coordinates to create or update the display data and display the CG data. CG data transmission system. 2. The CG data transmission system according to claim 1, wherein the CG data display means of the terminal device comprises means for updating the display data according to an instruction from a user of the terminal device.