WO1998054636A2 - Explorateur de donnees pour environnement virtuel - Google Patents

Explorateur de donnees pour environnement virtuel Download PDF

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Publication number
WO1998054636A2
WO1998054636A2 PCT/IB1998/000835 IB9800835W WO9854636A2 WO 1998054636 A2 WO1998054636 A2 WO 1998054636A2 IB 9800835 W IB9800835 W IB 9800835W WO 9854636 A2 WO9854636 A2 WO 9854636A2
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WO
WIPO (PCT)
Prior art keywords
virtual environment
transformation
child
components
data
Prior art date
Application number
PCT/IB1998/000835
Other languages
English (en)
Other versions
WO1998054636A3 (fr
Inventor
Richard David Gallery
Dale Robert Heron
Michael Konstantijn Verhagen
Christopher Thorne
Original Assignee
Koninklijke Philips Electronics N.V.
Philips Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Koninklijke Philips Electronics N.V., Philips Ab filed Critical Koninklijke Philips Electronics N.V.
Priority to EP98919444A priority Critical patent/EP0916117A2/fr
Priority to JP11500421A priority patent/JP2000515659A/ja
Publication of WO1998054636A2 publication Critical patent/WO1998054636A2/fr
Publication of WO1998054636A3 publication Critical patent/WO1998054636A3/fr

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Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F16/00—Information retrieval; Database structures therefor; File system structures therefor
    • G06F16/90—Details of database functions independent of the retrieved data types
    • G06F16/95—Retrieval from the web
    • G06F16/957—Browsing optimisation, e.g. caching or content distillation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements

Definitions

  • the present invention relates to apparatus for accessing, from a remote source, data defining a graphical representation of a virtual environment, with the user being enabled to select a viewpoint within the virtual environment and the apparatus having means for rendering a display of the virtual environment from that viewpoint.
  • a description of a service providing a virtual environment (or cyber-space) accessible by remote users is given in European patent application EP-A-0 697 613 (Sony Corp.).
  • the system described includes a server providing data defining a virtual reality space, and user terminals connected to the server via a high-speed communications network (using optical fibres or the like).
  • the server maintains data for a number of virtual environments and supports many differing terminal types by the use of conversion objects between information objects and user objects: the conversion objects provide individually tailored translation for communications back and forth between each type of terminal and each configuration of virtual environment supported.
  • VRML Virtual Reality Modelling Language
  • VRML is a file format for describing interactive three-dimensional objects and worlds to be experienced on the Internet/World Wide Web and it is generally analogous to the way HTML (HyperText Markup - Language) is used to describe documents for transmission over the Internet.
  • HTML HyperText Markup - Language
  • the functionalities of the different browsers depend to a large extent on their target host system and the likely uses of the same, as well as whether the browsers are purpose-built/written or whether they are modifications of earlier utilities.
  • the construction of the objects from components is defined by a hierarchy of 5 parent and child nodes or components, where each child may have children of its own.
  • Relative motion and scaling of these components is defined by a transformation (such as a matrix multiplication) with compound movement of components of an object being represented by a series of sequentially applied transformations.
  • a transformation such as a matrix multiplication
  • a data processing apparatus configured as a virtual environment data browser, the apparatus comprising a processor coupled with at least one memory device o and data network interface means capable of receiving data defining a virtual environment and objects therein when coupled to a data network including a source of such data, the apparatus further comprising user-operable input means and rendering means configured to periodically generate an image - based on said data defining the virtual environment and objects and from a viewpoint at a location and with an orientation in said virtual environment determined at least partially by input from said user-operable input means, wherein objects within the virtual environment are formed from a plurality of geometrical components, each defined according to its own coordinate system, with the components in an object being arranged in a hierarchy of parent and child components with each child being linked to its parent by a transformation specifying the conversion of the child component parameters to the parental coordinate system; characterised in that the apparatus is arranged to maintain a record, for each image generation, of the result of each transformation application, to determine which transformations have been altered as a result of movement
  • the generated virtual environment hosting the compound objects forms the upper level of all hierarchical object groupings: in such a case, a further transformation is suitably applied, during each update of the virtual environment, to the most senior component of the or each hierarchy to convert the transformed component parameters of the components of the hierarchy to the further coordinate system specified for the- virtual environment as a whole.
  • the means for effecting the conversion of child coordinate parameters to a parental coordinate system may suitably comprise calculation means operable to effect matrix multiplication, which calculation means may be effected in software or hardware, or a combination of both.
  • These means for effecting the conversion of child coordinate parameters to a parental coordinate system will preferably also include multiplication means operable to effect scaling of child coordinate parameters, such that components need only be specified in a single size (to save storage space) and scaled as required.
  • the record of transformation application is suitably held in the said at least one memory device (optionally linked to the result of the previous application of the transform) as an identifier for each transformation with an associated flag, which flag is set on the alteration of the transform and reset if the transform is unchanged following a subsequent update of the generated virtual environment.
  • a separate memory for example a high speed cache
  • FIG. 1 is a block schematic diagram of a data processing system suitable to embody the present invention
  • Figure 2 represents the component functions of a browser, as hosted by the system of Figure 1 , and embodying the invention
  • Figure 3 shows side and elevational views of an object, formed from four discrete components, for display in a virtual environment
  • Figure 4 illustrates a hierarchical node structure linking the components of Figure 3
  • Figure 5 is a flowchart representing the periodic virtual environment refresh routine implemented by the browser of Figure 2.
  • Figure 1 represents a data processing system, such as a personal computer, which acts as host for a software utility which configures the system as a browser for data defining a virtual environment.
  • the system comprises a central processing unit (CPU) 10 coupled via an address and data bus 12 to random-access (FvAM) and read-only (ROM) memory devices 14, 16.
  • FvAM random-access
  • ROM read-only
  • the capacity of these memory devices may be augmented by providing the system with means to read from additional memory devices, such as a CD-ROM (not shown).
  • first and second user input devices 18, 20 which may suitably comprise a keyboard and a cursor control and selection device such as a mouse or trackball.
  • Audio output from the system is via one or more speakers 22 driven by an audio processing stage 24; in addition to providing amplification, the audio processing stage is preferably also configured to provide a signal processing capability under the control of the CPU 10 to allow the addition of sound treatments such as echo to existing audio data.
  • Video output from the system is presented via display 26 driven by display driver stage 28 under control of the CPU 10: display 26 may be a flat screen showing a single image of the virtual environment from a selected viewpoint, or it may be a more complex device such as a binocular head- mounted display or a multiple interlaced view autostereoscopic screen.
  • a further source of data for the system is via online link to remote sites, for example via the Internet, to which end the system is provided with a network interface 30 coupled to the bus 12.
  • the precise construction of the interface is not an essential feature of the present invention, although it will be recognised that the interface configuration will depend on the type of data network to which the system is to be coupled: for example, where the system is for use by a private home user, the data link is likely to be a telephone connection to a local service provider. In such a case, the interface 30 will suitably incorporate a modem. For other types of data link, such as an ISDN connection, the interface will be configured accordingly.
  • FIG 2 the inter-relationship of a number of functions assembled to configure the hardware of Figure 1 as a browser is illustrated.
  • the functions in the example illustrated are particularly suited for browsing virtual environments defined in accordance with the VRML standard, version 2.0, issued as ISO/IEC WD14772 on 4th August 1996, although it will be understood that the present invention is not restricted by, or limited to, conformance with this standard.
  • the browser is based around a scene manager 40 coupled with respective stores for functions 42, assets 44, and a hierarchy of scene nodes 52, as will be described in greater detail below.
  • the function, asset and hierarchy stores will generally be held in RAM 14, although some of the assets (for example standardised texture maps for application to the surfaces of the scene components) may be provided via offline storage such as CD-ROM.
  • the browser implementation program is suitably held in non-volatile ROM 16, optionally linked to a conventional boot-up utility for the system.
  • Also coupled with the scene manager are four interfaces (IF.1-IF.4) 46-49 and a clock 50.
  • the first of the four interfaces 46 corresponds in part to interface 30 of Figure 1 in that it represents the source of data received via the Internet: as represented by dashed line 54, the received data may be passed on from the interface to other (not shown) destinations, such as a further browser for HTML content in the received data.
  • the first interface is the general arrival point for the data defining the virtual environment and, as such, it may also receive data from more local sources such as storage in the system RAM (14; Fig.1) or from a CD-ROM.
  • the data passes to a parsing stage 56 which divides it into data defining or relating to assets (which data is then passed to store 44) and data defining or relating to the run-time node hierarchy (which data is then passed to store 52).
  • data defining or relating to assets which data is then passed to store 44
  • data defining or relating to the run-time node hierarchy which data is then passed to store 52.
  • the data required in terms of texture, coordinates etc
  • Related information not immediately required is instead held in the form of an address for its current- storage location.
  • the address held by the browser will suitably be a URL (uniform resource locator) so that the browser can simply call up the data, via the first interface IF.1 , when the need for it becomes imminent; for more local information, an address in RAM 14 or ROM 16 is held.
  • URL uniform resource locator
  • the second interface 47 is an external API (application programming interface) comprising a set of interfacing subroutines enabling multiple-user extensions to the system, such as to simultaneously support two or more users having respective viewpoint locations and orientations within a common environment. It will be recognised that the particular form and specification of the subroutines will vary according to factors such as the number of users supported simultaneously, what form of user-operable input device or devices each is provided with, and so forth: the interfacing subroutines have no direct bearing on the operation of the present invention and will not be further described.
  • the third interface 48 is for operational segments used to program behaviour in a scene: these segments are referred to in VRML as script nodes.
  • the script nodes contain a program module which, in response to a change or user action within a scene, effect a change somewhere else in the scene depending on the contents of the program module.
  • the program modules may suitably contain Java ® language segments (Java is the object-oriented platform-independent and general-purpose programming environment developed by Sun Microsystems Inc).
  • the third interface 48 provides a path to (and in some instances from) a Java interpreter which converts the Java segments from their platform-independent form to a form recognised by the host system.
  • the fourth interface 49 handles the passing of signals from (and in some instances to) the user input devices.
  • Audio manager this controls the operation of the audio processor (24; Fig.1) where provided, or the handling of audio data processing in the host ⁇ systems CPU.
  • MPEG decoder software decoding of MPEG-compliant compressed image data.
  • Node run-time implementations an example of these are the interpolators provided for animations, where instead of requiring specification of a location for each component at each instant, starting and finishing locations (keyframes) and times to travel between them are specified with the system providing a mechanism to derive (via interpolation) the intermediate positions, as required for compliance with VRML specifications.
  • Collision detection for determining relative locations of components within the virtual environment in order to trigger so-called contact events and thereby avoid anomalous features such as permitting characters to walk 5 through supposedly solid walls.
  • Three-dimensional picking following rendering of the virtual environment, picking is the VRML term for the process for generating an appropriate response to user selection (for example point-and-select using a mouse) of artifacts displayed in the environment.
  • o - Viewpoint control handling changes to the viewpoint location and/or orientation from which the image of the virtual environment is to be generated, in response to program instruction or user input.
  • the movement may be an instantaneous "jump" from one predetermined viewpoint to another, or it may comprise the apparent movement relative to the virtual environment of the 5 viewpoint itself, realised by interpolating between two predetermined viewpoints.
  • the viewpoint control function will have different levels of complexity depending on whether it is handling a single viewpoint for generation of a planar two-dimensional image of the environment, or a binocular pair of viewpoints to allow the generation of three-dimensional o images.
  • Routing mechanism the procedure for propagating events through the node hierarchy.
  • version 2.0 of the VRML specification has a specific communications protocol between nodes. So-called “event-out” fields - on one node are “routed” to "event-in” fields of another. An operational realisation of this would be a mouse click starting an animation.
  • the routing 5 for this node communication would be that the event-out of a touch-sensor node goes to the event-in of a timer node, the timer is connected to an interpolator node, and the interpolator connects to the transform node of the VRML object to be animated.
  • the assets within store 44 are the basic building blocks and operational ⁇ o features from which the virtual environment is built up. These include:
  • Three-dimensional geometry defining the configuration and relative location of the polygons to be assembled for the virtual environment. It should be noted that each node (or screen component) will generally be defined in terms of its own co-ordinate system, which coordinates are converted by matrix 15 multiplication back through a hierarchy of component interconnections to convert all components to a common set of "world" coordinates.
  • Textures surface detail for mapping onto polygon surfaces during rendering.
  • the textures may be stored at variable levels of resolution where storage space permits and/or the system may be provided with means for 20 varying the resolution, such as interpolators operable to generate intermediate resolution texture values from a pair of pre-stored textures of different resolutions.
  • Audio data audio segments, sound effects etc. to accompany particular scenes or events within the virtual environment.
  • 25 - Java ® code the segments of code within script nodes which are called to handle various processes or actions within the rendered scene.
  • User interaction data for example, viewpoint control modes, identification of different user input devices and so forth.
  • MPEG data video image data with accompanying data identifying 30 compression, stored motion vectors etc.
  • the further store for run-time node structures 52 contains the VRML scene graph together with routes to allow dynamic behaviour.
  • the scene graph is a hierarchical file specifying the connections between the various geometrical - components making up an object within the virtual environment: the arrangement is a parent-child hierarchy with, for example, arms and legs being children of a body and hands and feet being respectively children of arms and legs.
  • Figure 3 shows a simple representation of a fan to be generated as a moving object within a virtual environment which fan is made up of four components, namely the base 60, body 62, blade 64 and a button 66. As shown by Figure 4, these components are arranged in the hierarchy with the body as a child of the base and the blade and button as separate children of the body.
  • each of the components of Figure 3 is originally specified according to its own coordinate system rather than in terms of the coordinate system of the virtual environment. This simplifies initial storage as, for example, a cylindrical component such as the body 62 may be defined in a coordinate system having an axis concurrent with the major axis of the cylinder with the only individual parameters required being the length and radius.
  • transformation T (suitably a matrix multiplication) which, when effected, translates the component parameters of the child to the coordinate system of the parent.
  • transformation T1 is that between the body 62 and base 60
  • transformation T2 is that between the blade 64 and body 62
  • transformation T3 is that between the button 66 and body 62.
  • transformation TO converts the parameters of the base and, through the matrix multiplication, all other components of the object to the coordinate system of the virtual environment.
  • the transformations In addition to handling modification of component parameters between coordinate systems, the transformations also handle scaling of components relative to one another so that components such as spheres need not be specified for every size in which they are required but only once with different transformation scaling factors being used for each different sized spherical - component required.
  • a particular problem which the present invention seeks to overcome is the excessive computational load caused by multiple level hierarchies requiring a large number of matrix multiplications before a distal child component is scaled and converted to the coordinate system of the virtual environment.
  • the following compound transformations are required for the object of Figure 3: (T0.T1).T2 x (blade vertices)
  • the browser embodying the present invention is arranged to store (in FiAM 14;
  • Fig.1 the result of a previous transformation multiplication such as (T0.T1) and also to flag, for each update of the virtual environment, which transformations have been modified and which remain as at the previous rendition.
  • the representation of the fan can simply call on the previously derived and stored result of (T0.T1) for multiplication with the updated transformation T2 rather than having to recalculate T0.T1 to repeatedly get the same result.
  • the technique will not produce a saving if more or less all of the components are moving relative to each other at most or all refreshes of the virtual environment, this is not a particularly common scenario.
  • the flowchart of Figure 5 illustrates the refresh routine implemented by the browser.
  • the routine comprises the steps of getting any input (A), evaluating the effect of that input (B), updating the database (C), and output of the results (D).
  • the routine starts by checking the time (from CLK 50) at step 100 to determine whether it is time for the refresh to commence. If so, this is followed by checking at step 102 whether there has been any input from the keys of a keyboard (18; Fig.1) and at step 104 whether there has been any input from a cursor control and selection device such as a mouse (20; Fig.1).
  • the evaluation stage begins at step 106 with a determination as to whether any selection has been made by the cursor control.
  • the user's position within the virtual environment is used to evaluate whether any trigger nodes (touch sensors or time sensors) have been activated - that is to say whether the user has clicked on a touch sensor or a time sensor has reached its start time.
  • the updating of the ⁇ database C begins with routing, at steps 110, and 1 12.
  • step 1 10 all those nodes having fields invalidated by the activation of a trigger node are notified of that invalidation.
  • all of the invalidated nodes are given respective new values: note that this procedure must be performed "bottom up" in relation to the hierarchy to ensure that all new values are propagated. The result of this is that a node having received notification that it has an invalid field requests a new value via the routing from its input node. This input node may, in turn, have to request a new value before it can calculate the new value that has been requested from it, and so forth up the hierarchy.
  • any changes to the user's position in terms of viewpoint location and/or orientation within the virtual environment are calculated, and any changes to the presented audio (such as the triggering of new audio 5 strands) are checked and the audio model updated at 116.
  • the final stage of the updating is to update the scene graph (the node hierarchy) which involves firstly updating the transformation matrices between parent and child nodes to reflect any relative movement of the respective components (step 118) - including the setting of flags to show that changes have been made - followed o by updating the bounding boxes around the compound components at step 120.
  • the final stage of the refresh procedure begins by sending the updated transformation matrices to the renderer at step 122 together with the updated user viewpoint at step 124. Following the image 5 rendering (step 126) the procedure reverts to step 100 until it is again time to run the refresh loop.

Abstract

Cet explorateur de données permet d'accéder à des données définissant des environnements virtuels via le W3 d'Internet. Lorsque les données définissant des objets à représenter dans l'environnement virtuel se présentent sous l'aspect de composants géométriques discrets, chaque objet étant agencé comme une hiérarchie liant les composants et des transformations (T0, T1, T2, T3) spécifiant la translation de positions de sommet pour composant fils vers le système de coordonnées de son parent, l'explorateur conserve un relevé des produits de transformation (T0, T1) calculés auparavant. Chaque fois que l'explorateur actualise sa représentation générée de l'environnement virtuel, il vérifie quels composants se sont déplacés et, à partir de là, quelles sont les multiplications de transformation à actualiser, s'il en est autrement, il rappelle le résultat du calcul précédent.
PCT/IB1998/000835 1997-05-29 1998-05-29 Explorateur de donnees pour environnement virtuel WO1998054636A2 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP98919444A EP0916117A2 (fr) 1997-05-29 1998-05-29 Explorateur de donnees pour environnement virtuel
JP11500421A JP2000515659A (ja) 1997-05-29 1998-05-29 仮想環境のデータブラウザ

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9711001.9 1997-05-29
GBGB9711001.9A GB9711001D0 (en) 1997-05-29 1997-05-29 Virtual environment data browser

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WO1998054636A2 true WO1998054636A2 (fr) 1998-12-03
WO1998054636A3 WO1998054636A3 (fr) 1999-03-25

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EP (1) EP0916117A2 (fr)
JP (1) JP2000515659A (fr)
KR (1) KR20000029642A (fr)
GB (1) GB9711001D0 (fr)
WO (1) WO1998054636A2 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1146480A1 (fr) * 2000-04-06 2001-10-17 European Molecular Biology Laboratory Microscope commande par ordinateur
US10740004B2 (en) 2015-07-07 2020-08-11 International Business Machines Corporation Efficiently managing movement of large amounts object data in a storage hierarchy
US11113876B2 (en) 2013-04-19 2021-09-07 Huawei Technologies Co., Ltd. Method for displaying a 3D scene graph on a screen

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0697613A2 (fr) * 1994-08-19 1996-02-21 Sony Corporation Système de cyber-space
US5588104A (en) * 1990-11-30 1996-12-24 Vpl Research, Inc. Method and apparatus for creating virtual worlds using a data flow network

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5588104A (en) * 1990-11-30 1996-12-24 Vpl Research, Inc. Method and apparatus for creating virtual worlds using a data flow network
EP0697613A2 (fr) * 1994-08-19 1996-02-21 Sony Corporation Système de cyber-space

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1146480A1 (fr) * 2000-04-06 2001-10-17 European Molecular Biology Laboratory Microscope commande par ordinateur
WO2001078008A1 (fr) * 2000-04-06 2001-10-18 European Molecular Biology Laboratory Microscope commande par ordinateur
US6991374B2 (en) 2000-04-06 2006-01-31 European Molecular Biology Laboratory Computer controlled microscope
US11113876B2 (en) 2013-04-19 2021-09-07 Huawei Technologies Co., Ltd. Method for displaying a 3D scene graph on a screen
US10740004B2 (en) 2015-07-07 2020-08-11 International Business Machines Corporation Efficiently managing movement of large amounts object data in a storage hierarchy

Also Published As

Publication number Publication date
GB9711001D0 (en) 1997-07-23
EP0916117A2 (fr) 1999-05-19
WO1998054636A3 (fr) 1999-03-25
JP2000515659A (ja) 2000-11-21
KR20000029642A (ko) 2000-05-25

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