Image analysis – Image compression or coding
Reexamination Certificate
2003-01-30
2004-06-29
Boudreau, Leo (Department: 2621)
Image analysis
Image compression or coding
C382S240000, C382S154000, C345S419000
Reexamination Certificate
active
06757432
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for transmitting and receiving stream data which forms a three-dimensional virtual space represented by three-dimensional computer graphics (hereinafter, referred to as three-dimensional CG or 3DCG) based on a network such as the Internet.
2. Description of the Related Art
In recent years, as the fields to which 3DCG is applicable, a virtual mall, electric commerce, and various home pages related thereto on the Internet such as a WWW (World Wide Web) have drawn attention. In particular, with the rapid development of the Internet, an environment is becoming available for easily handling 3DCG with a relatively high quality such as games and movies at home. In the conventional WWW, a machine called a server such as a personal computer and a work station is connected to a plurality of machines called clients such as personal computers. When a client requests, the client downloads data such as information of an image, a voice, a text, and an arrangement provided by the server, if required. The data is reconstructed on the client side, whereby a user can obtain required information. A communication method based on a TCP/IP (Transmission Control/Internet Protocol) is adopted for communication between the server and the client.
Conventionally, data provided by the server is mainly text data and image data. Recently, with the advancement in standardization of VRML (Virtual Reality Modeling Language), a browser of VRML, and the like, there is a tendency of transferring 3DCG data such as a shape and/or a scene.
Hereinafter, the VRML will be briefly described.
According to a conventional data format such as an image and a text as in HTML (Hyper Text Markup Language), a great amount of transfer time and transfer cost are required for transferring image data, in particular, animation data. Therefore, in the current system, there is a limit to the network traffic. In contrast, according to conventional 3DCG, visual point information and light source information including configurations are all processed by using three-dimensional data obtained by CG (Computer Graphics) data by calculation. On the receiving side, image data is generated based on three-dimensional data, and it is displayed.
With the advancement in CG technology, the quality of an image created by CG is rapidly improved. Therefore, it is becoming very efficient to transfer CG data as it is in view of a data amount.
Typically, when CG data is used, the data can be compressed at a data compression ratio of 1/100 or less, compared with the case where comparable image data is transferred. Thus, there is a tendency of standardizing a method for transferring 3DCG data through a network. As one solution, it is proposed to standardize 3 DCG data called VRML (VRML Ver. 2.0). In VRML Ver. 2.0, formats of data such as data having a configuration called a primitive, light source data, visual point data, and texture data, and a method for specifying a movement of a rigid body.
On the other hand, there is an animation technique for generating an image in real time, which has drawn attention recently in the CG field. By using an animation technique in real time, it is attempted to reproduce a real movement of a CG character particularly in CMs and movies. As an example, a complicated shape of a human is represented by a skeleton structure, and a motion amount of joints of a skeleton which change from moment to moment is defined, whereby a complicated motion can be naturally reproduced.
However, according to the conventional 3DCG modeling language on the Internet based on the VRML, a motion cannot be set in real time to a structure having a complicated shape such as a human.
Furthermore, it is impossible to transmit and receive motion data of a CG character (e.g., human) which performs real motions in real time through a network with a narrow band such as a telephone line.
SUMMARY OF THE INVENTION
A transmitter of the present invention includes a multi-dimensional stream data transmitting unit, for transmitting multi-dimensional stream data.
In one embodiment of the present invention, the transmitter includes: a multi-dimensional stream data identifying unit for classifying input data into a plurality of kinds of motion data; and a multi-dimensional stream data compressing unit for compressing the plurality of kinds of motion data on a block basis.
In another embodiment of the present invention, the multi-dimensional stream data compressing unit changes a compression ratio in accordance with the kind of the motion data.
In another embodiment of the present invention, the multi-dimensional stream data compressing unit selects a compression method in accordance with the kind of the motion data.
In another embodiment of the present invention, the multi-dimensional stream data compressing unit generates a node sequence which is time-series data, composed of at least one motion data among the plurality of kinds of motion data during a predetermined period, and extracts an arbitrary node from the node sequence to compress the plurality of kinds of motion data on a block basis.
In another embodiment of the present invention, the multi-dimensional stream data transmitting unit transmits interpolation information required for reproducing the extracted node and the node sequence.
In another embodiment of the present invention, the multi-dimensional stream data compressing unit reduces a high frequency component of the plurality of kinds of motion data to compress the plurality of kinds of motion data on a block basis.
In another embodiment of the present invention, the multi-dimensional stream data compressing unit subjects at least one motion data among the plurality of kinds of motion data to coordinate transformation to compress the plurality of kinds of motion data on a block basis.
In another embodiment of the present invention, the multi-dimensional stream data compressing unit transforms data represented by three-dimensional vector coordinates among the plurality of kinds of motion data to data represented by polar coordinates, thereby compressing the plurality of kinds of motion data on a block basis.
In another embodiment of the present invention, the multi-dimensional stream data includes header information or stream format describing data, describing a kind of the multi-dimensional stream data to be transmitted, an order of the plurality of kinds of motion data to be transmitted, and a length of the plurality of kinds of motion data to be transmitted.
In another embodiment of the present invention, the multi-dimensional stream data has time information and space information of a plurality of dimensions.
In another embodiment of the present invention, the space information of a plurality of dimensions includes position information, rotation information, and scale information.
In another embodiment of the present invention, the multi-dimensional stream data capable of representing a CG scene includes data representing a position, rotation and a scale of the CG scene.
In another embodiment of the present invention, the multi-dimensional stream data capable of representing a CG scene is multi-dimensional animation stream data.
In another embodiment of the present invention, the multi-dimensional stream data has a data portion having a plurality of channels and a header portion describing a stream data format of the data portion and, each of the plurality of channels has a plurality of pieces of information regarding a three-dimensional CG character at a certain time.
In another embodiment of the present invention, the three-dimensional CG character is capable of being represented by a hierarchical structure having at least one joint, and each of the plurality of motion data has at least one of data having a dimension of a position vector at a reference position of the three-dimensional CG character, data having a dimension of a direction vector representing a posture at the reference position, data having a dimension of an angle vector of the at l
Asahara Shigeo
Hijiri Toshiki
Mochizuki Yoshiyuki
Naka Toshiya
Nishitani Kazuhiro
Boudreau Leo
Dang Duy M.
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