Classifications

• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T9/00—Image coding
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T13/00—Animation
  • G06T13/20—Three-dimensional [3D] animation
  • G06T13/40—Three-dimensional [3D] animation of characters, e.g. humans, animals or virtual beings
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T2213/00—Indexing scheme for animation
  • G06T2213/12—Rule based animation

Definitions

• Animation data signal of a graphic scene with quantification object corresponding method and device.
• the field of the invention is that of the coding of data representative of animated graphic scenes, in order to allow their restitution, for example on a multimedia terminal. More specifically, the invention relates to the quantification of such data, so as to allow their storage and / or their transmission.
• graphic scene is meant here the arrangement of graphic, video and image objects in time and in space.
• Such graphic scenes can be in two or three dimensions, and contain various types of graphic primitives.
• the invention finds applications in all cases where it is necessary to code the elements of a graphic scene. It applies in particular to scenes using the known scene description formats VRML and BIFS, developed in MPEG-4.
• the ISO / TEC standard DIS 14772-1 describes the VRML 2.0 format.
• the standardization group MPEG-4 defined the scene description format called BIFS (Binary Format for Scene), which is inspired by VRML 2.0.
• BIFS Binary Format for Scene
• this scene description format is to describe the spatiotemporal relationships between the various graphic objects in a scene. For this, it defines a certain number of nodes, or objects, representing all the graphic primitives that we want to represent. Each of these nodes includes pre-defined fields which represent the characteristics of these nodes.
• the BIFS format makes it possible to transmit a scene structure in the form of a parametric description, or a script.
• BIFS-type graphic scenes can be used for multimedia consultation (distance education, tele-shopping, tele-work), 3D games, advanced navigation interfaces in services.
• the following applications can benefit from the invention: consultation on a network of the "Internet" type of graphic scenes of VRML 2.0 type, for which it is necessary to define a format compact data representation, to reduce transmission time. storing such scenes on media such as CD-Roms.
• a binary scene representation format is already known for the VRML 2.0 standard, described in the document cited above.
• the author proposes to send the quantization parameters in the form of a node.
• the quantification parameters chosen only apply to a very limited number of fields. This has the effect of imposing the transmission of a large number of fields in an unquantified manner. This of course limits the efficiency of digital data compression.
• the invention particularly aims to overcome these drawbacks of the state of the art.
• an objective of the invention is to provide a data signal, as well as a method and a device for its implementation, which make it possible to greatly reduce the data necessary for coding, and therefore the transmission and / or the storage of animated graphic scenes, in particular in standards such as VRML and
• Another objective of the invention is to provide a technique for coding data representative of graphic scenes, which allow transmission of scenes on a low-speed network, and the reconstruction of these scenes in terminals which do not require significant resources. hardware or software.
• the invention also aims to provide such a technique, which is effective with any type of scene and any type of element constituting this scene, without it being necessary to treat specifically (that is to say in a manner not quantified), certain elements.
• a data signal for animation of a graphic scene intended for means of constructing images which can be presented on at least one screen, signal in which said scene is described in the form of a set of animation objects with each of which at least one characterization field is associated defining mr ⁇ parameter of said object, and comprising at least one quantification object, the characterization fields of which define rules for the quantification of characterization fields of said animation objects, each applicable to at least two distinct characterization fields, so that 'at least most of the characterization fields with numerical value of said animation objects can be quantified.
• the quantization parameters as an object or node.
• the advantage of transmitting these parameters as a node is to take advantage of all the functionalities linked to the transmission of nodes in a scene description flow: the declaration of a node in the scene is equivalent to the declaration of all its fields, with pre-defined default values; the declaration of any field allows to redefine a value other than the default value of this field; it is possible to identify this node then to re-use it as soon as it is necessary in the scene, simply by indicating its identifier.
• such a quantization object comprises at least one of the quantification rules belonging to the group comprising: - quantification rule for a three-dimensional position; rule for quantifying a two-dimensional position; color quantization rule; texture quantization rule; angle quantification rule; - rule for quantifying a change of scale; quantification rule for an animation "key”; rule for quantifying a normal.
• each of said quantification objects comprises a boolean scope field, indicating: - for a first value, that the quantification object only applies V next object; for the second value, that the quantization object applies to all of the following objects, until a new quantization object is encountered. It is thus possible to further limit the number of data required.
• each rule for quantifying a type of parameter at least some of the information belonging to the group is delivered comprising: an indicator for implementing or not quantizing; - a minimum value of said parameter min; a maximum maximum value of said parameter; a number of bits (Nb) assigned to the quantization of said parameters.
• the invention also relates to a coding method for producing such a signal.
• This method comprises in particular: a definition step, delivering at least one quantification object, the characterization fields of which define the characterization field quantification rules for said animation objects, each applicable to at least two distinct characterization fields, so that at least most of the numerical value characterization fields of said animation objects can be quantified; and a quantification step, ensuring the quantification of the data specific to each of said characterization fields of said animation objects, according to said quantization rules.
• the invention also relates to an image construction device capable of receiving this signal.
• FIG. 1 schematically illustrates a terminal capable of processing the signal of the invention
• - Figure 2 shows in a simplified way the principle of construction of a signal according to the invention.
• MPEG-4 has defined a scene description format, BIFS, inspired by the VRML 2.0 format.
• the purpose of this scene description format is to describe the spatio-temporal relationships between the graphic objects of a scene.
• the BIFS format defines a certain number of "nodes" representing all the graphic primitives that we want to transmit. Each of these nodes has pre-defined fields which represent the characteristics of these nodes.
• the primitive Circle has for field "radius" of type floating number.
• the "Video Object" primitive has the start and end times of this video as parameters.
• the following description is made in the context of MPEG-4. However, it can easily be adapted to the VRML language.
• Figure 1 shows an example application.
• the MPEG-4 terminal loads the graphic scene 11 described in a BIFS format.
• the scene is described in terms of objects or nodes. These nodes are represented by fields. These fields will be quantified using the quantization parameters sent in the new node described below.
• the scene is constructed by the BIFS interpreter 13.
• the audiovisual stream 14, processed by the audio-video decoder 15, is also taken into account for the composition and rendering of the scene 12.
• An animated image 16 is thus obtained, presented to the user. If necessary, the latter can intervene (17), using an appropriate interface.
• One difficulty in effectively quantifying the fields of the scene description nodes is that no statistics are available on these fields.
• the data to be quantified are grouped into 8 large groups:
• a definition (21) of the quantization rules is provided, in the form of a quantization node, an example of which is given below.
• each animation node is quantized (22), according to the rules defined in the quantization node. It is of course possible to redefine some or all of the parameters during the description, by delivering a new (23) quantization node.
• the "isLocal” field is a boolean that specifies the scope of the quantization parameters. When set to “TRUE”, the quantization parameters only apply to the next declared node. In this case, the quantization parameters used after this node are those that were valid before the declaration of this parameter. If set to "FALSE”, these quantization parameters apply to all nodes until a new quantization node is declared.
• V V m ⁇ n " * N V q
• QuantizationParameter can be taken into account to readjust the bounding box on which the vector quantization is performed and that specified by the quantization parameters.
• vector quantization in lattice D3 will be particularly suitable for colors and 3D positions, while 2D or texture positions may use vector quantization in lattice D2.
• any other quantification scheme could be used for these fields.
• the three components of the resulting 3D or 2D vector can be uniformly quantified. Normal and axes of rotation
• This technique consists of cutting the unit sphere into 8 octants, then each octant into 3 quadrilaterals, on which we can quantify uniformly on a regular grid.
• the normalNbBits parameter therefore indicates that we will represent the value of the normal on a regular square grid of 2normalNbBits side elements. We will therefore represent the normals in fact on normalNbBits + 3 + 2 bits.
• any other quantification scheme could be used for these fields.
• the three components of the resulting 3D vector can be uniformly quantified.
• SFRotation consist of four floats that specify an axis of rotation for the first three and an angle; For this field, it is proposed to apply the quantization of the normals for the axis of rotation, and that of the angles for the fourth angle value.
• the efficiency of the syntax for representing the quantization node lies in particular in the fact that all of its parameters can be applied.
• IndexedFaceSet but also all the axes of rotation.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Theoretical Computer Science (AREA)
• Multimedia (AREA)
• Processing Or Creating Images (AREA)
• Compression Or Coding Systems Of Tv Signals (AREA)
• Compression, Expansion, Code Conversion, And Decoders (AREA)

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• 1997
  • 1997-07-11 FR FR9709121A patent/FR2765984B1/fr not_active Expired - Lifetime
• 1998
  • 1998-07-10 US US09/462,309 patent/US6556207B1/en not_active Expired - Lifetime
  • 1998-07-10 CN CN2007101960501A patent/CN101221667B/zh not_active Expired - Lifetime
  • 1998-07-10 DE DE69800934T patent/DE69800934T2/de not_active Expired - Lifetime
  • 1998-07-10 ES ES98938734T patent/ES2159438T3/es not_active Expired - Lifetime
  • 1998-07-10 IL IL13379198A patent/IL133791A/xx not_active IP Right Cessation
  • 1998-07-10 AU AU87347/98A patent/AU738770B2/en not_active Expired
  • 1998-07-10 WO PCT/FR1998/001519 patent/WO1999003067A1/fr not_active Ceased
  • 1998-07-10 EP EP98938734A patent/EP0995170B1/fr not_active Expired - Lifetime
  • 1998-07-10 KR KR1020007000287A patent/KR100543577B1/ko not_active Expired - Lifetime
  • 1998-07-10 CN CN98807042A patent/CN1262758A/zh active Pending
  • 1998-07-10 JP JP2000502478A patent/JP3955177B2/ja not_active Expired - Lifetime
• 2004
  • 2004-06-09 JP JP2004171344A patent/JP2004295917A/ja not_active Withdrawn

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