Three-dimensional program guide

RELATED APPLICATIONS

P-0001[0001] This application is related to the following U.S. Patent Application:

P-0002[0002] Application Ser. No. ______, bearing Attorney Docket No.

P-0003[0003] MS1-1239US, filed ______, entitled “Three-Dimensional Television Viewing Environment”, and naming Peter T. Barrett as inventor.

TECHNICAL FIELD

[0004] This invention relates to electronic program guides and, in particular, to a three-dimensional electronic program guide.

BACKGROUND

[0005] With technological advances, television viewing has become more interactive. Many television viewing systems include a client device, such as a set-top box, that provides access to a programming guide through a user interface displayed on the television. Typically, a viewer accesses the programming guide by tuning to a particular channel over which the program guide data is being transmitted. Traditional electronic program guides display program data in a grid organized according to broadcast channel and time of day. The user can scroll through the program guide, identify a program of interest, and then tune to the channel on which the interesting program is being broadcast. The programming guide user interface may also display advertisements and/or program recommendations in addition to the program guide data.

[0006] Client devices that provide viewer interaction with a television may also include gaming consoles, such as the Microsoft Xbox™ gaming system. These gaming consoles support interactive three-dimensional video games, and may also include one or more tuners, such that the gaming consoles may replace traditional television set-top boxes. As such, the three-dimensional graphics functionality supported by the gaming console (or any other advanced client device, such as an advanced television set-top box or personal computer) may be utilized to enhance the television viewing experience by rendering an intuitive, three-dimensional electronic program guide.

SUMMARY

[0007] A three-dimensional electronic program guide (EPG) is described. EPG data is categorized according to similarities between programs. The similarities may be based on genre, content, target audience, and so on. Categorized EPG data is rendered in multiple two-dimensional areas within a three-dimensional environment. Viewers can navigate the three-dimensional EPG using an input device such as a joystick.

BRIEF DESCRIPTION OF THE DRAWINGS

P-0008[0008] The same numbers are used throughout the drawings to reference like features and components.

P-0009[0009]FIG. 1 illustrates a three-dimensional graphics environment.

P-0010[0010]FIG. 2<i>a </i>illustrates a two-dimensional plane within the three-dimensional graphics environment.

P-0011[0011]FIG. 2<i>b </i>illustrates a display of the two-dimensional plane within the three-dimensional graphics environment.

P-0012[0012]FIG. 2<i>c </i>illustrates a zoomed-in display of the two-dimensional plane within the three-dimensional graphics environment.

P-0013[0013]FIG. 3 illustrates an electronic program guide rendered using multiple two-dimensional areas within a three-dimensional environment.

P-0014[0014]FIG. 4 illustrates the display of exemplary navigational landmarks.

P-0015[0015]FIG. 5 illustrates components of an exemplary television viewing system that supports a three-dimensional television viewing environment.

P-0016[0016]FIG. 6 illustrates select components of a client device implemented to support a three-dimensional television viewing environment.

P-0017[0017]FIG. 7 illustrates a method for rendering EPG data in a three-dimensional television viewing environment.

DETAILED DESCRIPTION

P-0018[0018] The following discussion is directed to methods and systems that allow users to view media content and related information in a three-dimensional graphics environment. The three-dimensional television viewing environment described herein may be implemented using a client device with three-dimensional graphics capabilities configured to receive media content, such as broadcast television data or on-demand video. Media content, program guide data, program recommendations, advertisements, and any other related information is presented to a viewer within a three-dimensional viewing environment.

Three-Dimensional Presentation of Media Content and Data

P-0019[0019]FIG. 1 illustrates a three-dimensional viewing environment <b>100</b> in which media content and related information may be presented to a viewer. Points A, B, C, D, E, F, G, and H define a particular area within three-dimensional viewing environment <b>100</b> that extends substantially, if not infinitely, in each direction. An eye <b>102</b> represents a virtual location and viewing direction of a viewer within three-dimensional area <b>100</b>. For example, as illustrated, the viewer is virtually located approximately equidistance from plane ABCD and from plane EFGH, and is looking toward plane EFGH. Two-dimensional area <b>104</b> lies within plane EFGH, and represents a two-dimensional area in which data, such as a broadcast television program, a program guide, advertisements, or program recommendations, may be presented. Similarly, two-dimensional area <b>106</b> lies within plane ABCD, and represents another two-dimensional area in which data may be presented. It is recognized that any number of data/content areas may be defined within three-dimensional environment <b>100</b>. Furthermore, although data/content areas <b>104</b> and <b>106</b> are shown on parallel planes within environment <b>100</b>, it is recognized that data/content areas may be defined on any plane within environment <b>100</b>, and that planes containing defined two-dimensional areas may be at any angle to other planes containing defined two-dimensional areas. For example, area <b>108</b> is a two-dimensional area defined within a plane containing points A, B, F, and E and area <b>110</b> is a two-dimensional area defined within a plane that contains points A, C, and H. A viewer interacts with viewing environment <b>100</b> using a television remote control, a joystick, game controller, or other input device to move and/or rotate the virtual location of the viewer <b>102</b> within the environment <b>100</b>. For example, if a viewer is viewing a broadcast television program that is being rendered in area <b>104</b>, the viewer can use a joystick to rotate the virtual location of the viewer <b>180</b> degrees to bring into view an electronic program guide being presented in area <b>106</b>. As another example, if a viewer is viewing data that is being rendered in area <b>104</b>, the viewer can user the joystick to move the virtual location of the viewer closer to (zoom in on) or back away from (zoom out on) the displayed data. Using an input device, a viewer can move and/or rotate the virtual location of the viewer <b>102</b> in any direction within the three-dimensional viewing environment <b>100</b>.

P-0020[0020]FIG. 2<i>a </i>illustrates multiple data/content areas defined on a single plane within three-dimensional environment <b>100</b>. As in FIG. 1, points A, B, C, and D define a two dimensional plane within three-dimensional environment <b>100</b>. Furthermore, the rectangular area defined by points A, B, C, and D represents an area that is visible to a user through a display device, such as a television screen.

P-0021[0021]FIG. 2<i>b </i>illustrates an example display on display device <b>206</b> of the visible area illustrated in FIG. 2<i>a. </i>

P-0022[0022] Area <b>106</b> is defined as a two dimensional area, in which program listings are presented, such as a typical electronic program guide. Area <b>202</b> is defined as a two-dimensional area, in which advertisements are presented. Area <b>204</b> is defined as a two-dimensional area in which recommended programs are presented. As described with reference to FIG. 1, three-dimensional viewing environment <b>100</b> can include any number of two-dimensional areas for displaying any type of media or media data. Furthermore, although illustrated as being on the same plane, the multiple two-dimensional areas may each exist at any location within the thee-dimensional environment <b>100</b>.

P-0023[0023] Using an input device, a viewer can zoom in or out, scroll in any direction, including up, down, left, and right, and rotate the viewing perspective in any direction. For example, to view only the program listings in area <b>106</b>, a viewer can interact with the viewing environment <b>100</b> using an input device (e.g., a joystick or remote control) to zoom in on area <b>106</b> until area <b>106</b> fills the entire screen. FIG. 2<i>c </i>illustrates an example display after a viewer zooms in on two-dimensional area <b>106</b>.

P-0024[0024] In one implementation, multiple two-dimensional areas can be used to allow a user to navigate between media content and related data that is made available to the viewer via triggers in the media content itself. For example, while viewing a football game, an icon may be rendered that indicates that commercial products associated with the teams that are playing are available for purchase. Using an input device, the viewer can select the icon, which then causes the viewer perspective within the three-dimensional viewing environment to change, bringing into view a second two-dimensional area. Through the new viewing perspective, the viewer can view a commercial for the available products, or in an alternate implementation, a website through which the viewer can purchase the products.

P-0025[0025] In one implementation, while the viewer is navigating through the additional data associated with the selected icon or trigger, the program that was originally being displayed is paused. The viewer can then resume viewing the program after navigating and experiencing the triggered additional content and/or data.

Presenting an EPG in Multiple Two-Dimensional Areas

P-0026[0026] EPG data can be categorized in many ways, such as according to program type (e.g., television series, movie, pay-per-view, sports program, etc.), according to genre (e.g., drama, romance, mystery, horror, comedy, etc.), according to intended audience (e.g., children, teen, men, women, adults, etc.), according to channel and/or time, and so on. By providing a viewer multiple ways to view EPG data, the viewer is able to quickly identify media content of interest.

P-0027[0027]FIG. 3 illustrates an exemplary display of EPG data using multiple two-dimensional areas within a three-dimensional viewing environment. In an exemplary implementation, EPG data is displayed across multiple two-dimensional areas, with each two-dimensional area representing, for example, a different category of data. The categories and layout of two-dimensional areas illustrated in FIG. 3 is only one example, and it is recognized that more and/or different data categorizations may be displayed in any number of configurations.

P-0028[0028] Points K, L, M, and N define a plane within a three-dimensional viewing environment <b>100</b>. Points P, Q, R, and S define another plane within three-dimensional viewing environment <b>100</b>. As illustrated in FIG. 3, plane PQRS is parallel to and, from the illustrated perspective, behind plane KLMN. Two-dimensional areas <b>302</b>, <b>304</b>, <b>306</b>, and <b>308</b> are rendered in plane KLMN and two-dimensional areas <b>310</b>, <b>312</b>, and <b>314</b> are rendered in plane PQRS. As described above, with reference to FIGS. 1, 2<i>a</i>, <b>2</b><i>b</i>, and <b>2</b><i>c, </i>a viewer can navigate among the displayed two-dimensional areas using an input device, such as a joystick or game controller. For example, a viewer can zoom in on two-dimensional area <b>306</b> to view EPG data that describes programs that are appropriate for children. Similarly, a viewer can zoom past plane KLMN to zoom in on two-dimensional area <b>310</b> to view EPG data that describes programs that are categorized as comedies. Additionally, in the described implementation, two-dimensional areas may be arranged to take advantage of peripheral vision such that when a viewer is navigating within the three-dimensional viewing environment, the viewer may catch a glimpse of a portion of another panel near an edge of the screen, which may suggest the depth or variety of information available at other locations within the three-dimensional viewing environment.

P-0029[0029] Furthermore, information pertaining to a particular program may be displayed in multiple two-dimensional areas. For example, according to the configuration illustrated in FIG. 3, a movie that is a comedy may be represented in two-dimensional area <b>304</b> and also in two-dimensional area <b>310</b>. In an alternate implementation, two-dimensional areas may also be defined such that each area displays detailed information about a particular program, rather than EPG data describing a category of programs.

Presenting Navigational Landmarks

P-0030[0030] Navigational landmarks may be rendered, along with media content and/or other data, to indicate that additional content and/or data is available to a viewer if the viewer navigates in a particular direction within the three-dimensional viewing area. In one implementation, the navigational landmarks may simply indicate that additional content or data is available by navigating in a particular direction. In an alternate implementation, the navigational landmarks may also indicate descriptive information about the type of data or content that is available.

P-0031[0031]FIG. 4 illustrates an example display in which navigational landmarks indicate the presence of additional data and/or content. Box <b>402</b> represents the screen area of a display device <b>206</b>. Media content and/or other data (e.g., EPG data or advertisements) may be rendered within a two-dimensional area <b>403</b>. Navigational landmarks <b>404</b>, <b>406</b>, and <b>408</b> are displayed to indicate to a viewer that additional two-dimensional areas for rendering media content or associated data are available if the viewer navigates (e.g., using a game controller, joystick, or other input device) in the direction indicated. For example, as illustrated in FIG. 4, navigational landmark <b>404</b> indicates that additional data or content is available to a viewer if the viewer navigates to the right while navigational landmark <b>406</b> indicates that additional data or content is available to a viewer if the viewer navigates up. Similarly, navigational landmark <b>408</b> indicates that additional data or content is available to a viewer if the viewer navigates down and to the left.

P-0032[0032] In one implementation, navigational landmarks are always visible to a viewer, providing a persistent reminder that additional content and/or data is available and an indication of how the viewer can navigate to the available content and/or data. In an alternate implementation, some or all of the navigational landmarks are displayed only when requested by a viewer, for example in response to the press of a button or movement of a joystick or other input device. Alternatively, a navigational landmark may be rendered when available data or content changes. For example, if an adjacent but out of view two-dimensional area is used to render broadcast media content, a navigational landmark may be automatically rendered for a short period of time (e.g., 30 seconds) when a new broadcast program begins in the available two-dimensional area.

P-0033[0033] Although illustrated in FIG. 4 as arrows, navigational landmarks may include any type of demarcation, including icons, text, colored indicators, and so on. Furthermore, text or audio may be associated with a navigational landmark to provide further information to the viewer regarding what type of content or data is available. For example, a user may press a remote control button to display navigational landmarks. If the user presses the button a second time, text associated with the navigational landmarks may be displayed as well to indicate, for example, that a listing of upcoming sports programs is available by navigating to the right, and a listing of upcoming movies is available by navigating to the left.

P-0034[0034] In one implementation, the viewer can customize the relative placement of two dimensional areas such that frequently accessed content and/or data is always easily available. For example, the viewer can customize a two-dimensional area for rendering program listing data for programs currently being broadcast to always be available when the viewer navigates to the left. Similarly, a default navigational directional can be defined so that regardless of where the viewer is navigating within the three-dimensional viewing environment, navigating in the default direction will always bring into view a two-dimensional area for viewing current broadcast media content. Furthermore, when customizing relative placement of two-dimensional areas, the viewer can choose to inactivate navigational landmarks associated with the customized directions, because the viewer will know, based on the customization, that a particular set of data or content is always available by navigating in a particular direction.

P-0035[0035] In addition to customizing the relative placement of particular two-dimensional areas, an input device may be programmed such that a particular input causes a particular two-dimensional area to be moved into the viewing area. For example, pressing a particular button on a remote control or game controller causes the viewer perspective to move within the three-dimensional area to bring the two-dimensional area that renders broadcast media content into view.

Exemplary Television Viewing System

P-0036[0036]FIG. 5 shows an exemplary television viewing system <b>500</b>. System <b>500</b> includes a client device, such as gaming console <b>502</b> and up to four controllers, as represented by controllers <b>504</b>(<b>1</b>) and <b>504</b>(<b>2</b>). The game console <b>502</b> is equipped with an internal hard disk drive and a portable media drive <b>506</b> that supports various forms of portable storage media as represented by optical storage disc <b>508</b>. Examples of suitable portable storage media include DVD, CD-ROM, game discs, and so forth.

P-0037[0037] The game console <b>502</b> has four slots <b>510</b> on its front face to support up to four controllers, although the number and arrangement of slots may be modified. A power button <b>512</b> and an eject button <b>514</b> are also positioned on the front face of the game console <b>502</b>. The power button <b>512</b> switches power to the game console and the eject button <b>514</b> alternately opens and closes a tray of the portable media drive <b>506</b> to allow insertion and extraction of the storage disc <b>508</b>.

P-0038[0038] The game console <b>502</b> connects to a television <b>516</b> or other display via A/V interfacing cables <b>518</b> and <b>520</b>. A power cable <b>522</b> provides power to the game console. Cable or modem connector <b>524</b> facilitates access to a network, such as the Internet, a cable broadcast network, or a video-on-demand service.

P-0039[0039] Each controller <b>504</b> is coupled to the game console <b>502</b> via a wire or wireless interface. In the illustrated implementation, the controllers are USB (Universal Serial Bus) compatible and are connected to the console <b>502</b> via serial cables <b>530</b>. Controller <b>504</b> may be equipped with any of a wide variety of user interaction mechanisms. As illustrated in FIG. 5, each controller <b>504</b> is equipped with two thumbsticks <b>532</b>(<b>1</b>) and <b>532</b>(<b>2</b>), a D-pad <b>534</b>, buttons <b>536</b>, and two triggers <b>538</b>. These mechanisms are merely representative, and other known gaming mechanisms may be substituted for or added to those shown in FIG. 5. Each controller <b>504</b> provides a viewer with a mechanism for controlling a virtual viewer location <b>102</b> within a three-dimensional viewing environment <b>100</b>.

P-0040[0040] A memory unit (MU) <b>540</b> may be inserted into the controller <b>504</b> to provide additional and portable storage. Portable memory units enable users to store game parameters and port them for play on other consoles. In the described implementation, each controller is configured to accommodate two memory units <b>540</b>, although more or less than two units may be employed in other implementations.

P-0041[0041] Although shown and described as a game console, client device <b>502</b> may include any type of client device that includes a three-dimensional graphics processor and is capable of rendering three-dimensional images. For example, a television set-top box may be implemented with a three-dimensional graphics processor such that the set-top box may replace the game console illustrated in FIG. 5.

Exemplary Client Device

P-0042[0042]FIG. 6 shows functional components of game console <b>502</b> in more detail. Game console <b>502</b> has a central processing unit (CPU) <b>600</b> and a memory controller <b>602</b> that facilitates processor access to various types of memory, including a flash ROM (Read Only Memory) <b>604</b>, a RAM (Random Access Memory) <b>606</b>, a hard disk drive <b>608</b>, and the portable media drive <b>506</b>. The CPU <b>600</b> is equipped with a level <b>1</b> cache <b>610</b> and a level <b>2</b> cache <b>612</b> to temporarily store data and hence reduce the number of memory access cycles, thereby improving processing speed and throughput.

P-0043[0043] The CPU <b>600</b>, memory controller <b>602</b>, and various memory devices are interconnected via one or more buses, including serial and parallel buses, a memory bus, a peripheral bus, and a processor or local bus using any of a variety of bus architectures. By way of example, such architectures can include an Industry Standard Architecture (ISA) bus, a Micro Channel Architecture (MCA) bus, an Enhanced ISA (EISA) bus, a Video Electronics Standards Association (VESA) local bus, and a Peripheral Component Interconnects (PCI) bus also known as a Mezzanine bus.

P-0044[0044] As one suitable implementation, the CPU <b>600</b>, memory controller <b>602</b>, ROM <b>604</b>, and RAM <b>606</b> are integrated onto a common module <b>614</b>. In this implementation, ROM <b>604</b> is configured as a flash ROM that is connected to the memory controller <b>602</b> via a PCI (Peripheral Component Interconnect) bus and a ROM bus (neither of which are shown). RAM <b>606</b> is configured as multiple DDR SDRAM (Double Data Rate Synchronous Dynamic RAM) that are independently controlled by the memory controller <b>602</b> via separate buses (not shown). The hard disk drive <b>608</b> and portable media drive <b>506</b> are connected to the memory controller via the PCI bus and an ATA (AT Attachment) bus <b>616</b>.

P-0045[0045] One or more tuners <b>620</b> allow game console <b>502</b> to receive media content, as well as data that describes the media content, such as electronic program guide data. For example, the tuners <b>620</b> can be implemented to receive data over a satellite or cable broadcast network. Graphical media content and data that is received is processed using a 3D graphics processing unit <b>622</b> and a video encoder <b>624</b>, which form a video processing pipeline for high speed and high resolution graphics processing. Data is carried from the graphics processing unit <b>622</b> to the video encoder <b>624</b> via a digital video bus (not shown). Corresponding audio content and data that is received is processed using an audio processing unit <b>626</b> and an audio codec (coder/decoder) <b>628</b>, which form a corresponding audio processing pipeline with high fidelity and stereo processing. Audio data is carried between the audio processing unit <b>626</b> and the audio codec <b>628</b> via a communication link (not shown). The video and audio processing pipelines output data to an A/V (audio/video) port <b>630</b> for transmission to the television <b>206</b> or other display. In the illustrated implementation, the video and audio processing components <b>620</b>-<b>630</b> are mounted on the module <b>614</b>.

P-0046[0046] Also implemented on the module <b>614</b> are a USB host controller <b>632</b> and a network interface <b>634</b>. The USB host controller <b>632</b> is coupled to the CPU <b>600</b> and the memory controller <b>602</b> via a bus (e.g., PCI bus) and serves as host for the peripheral controllers <b>504</b>(<b>1</b>)-<b>504</b>(<b>4</b>). The network interface <b>634</b> provides access to a network (e.g., Internet, home network, cable broadcast network, etc.) and may be any of a wide variety of various wire or wireless interface components including an Ethernet card, a modem, a Bluetooth module, a cable modem, and the like. The network interface <b>634</b> may be configured to enable the one or more tuners <b>620</b> to receive media content and data.

P-0047[0047] The game console <b>502</b> has two dual controller support subassemblies <b>640</b>(<b>1</b>) and <b>640</b>(<b>2</b>), with each subassembly supporting two game controllers <b>504</b>(<b>1</b>)-<b>504</b>(<b>4</b>). Input received from a game controller <b>504</b> directs the 3D graphics processing unit <b>622</b> to perform the indicated visual navigation. A front panel I/O subassembly <b>642</b> supports the functionality of the power button <b>512</b> and the eject button <b>514</b>, as well as any LEDs (light emitting diodes) or other indicators exposed on the outer surface of the game console. The subassemblies <b>640</b>(<b>1</b>), <b>640</b>(<b>2</b>), and <b>642</b> are coupled to the module <b>614</b> via one or more cable assemblies <b>644</b>.

P-0048[0048] Eight memory units <b>540</b>(<b>1</b>)-<b>540</b>(<b>8</b>) are illustrated as being connectable to the four controllers <b>504</b>(<b>1</b>)-<b>504</b>(<b>4</b>), i.e., two memory units for each controller. Each memory unit <b>540</b> offers additional storage on which games, game parameters, and other data may be stored. When inserted into a controller, the memory unit <b>540</b> can be accessed by the memory controller <b>602</b>.

P-0049[0049] A system power supply module <b>650</b> provides power to the components of the gaming console <b>502</b>. A fan <b>652</b> cools the circuitry within the game console <b>502</b>.

Exemplary Method for Rendering Media Content and Data

P-0050[0050]FIG. 7 illustrates a method <b>700</b> for rendering EPG data within a three-dimensional television viewing environment. Rendering EPG data within a three-dimensional television viewing environment may be described in the general context of computer-executable instructions, such as application modules, being executed by a computer. Generally, application modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. A three-dimensional television viewing environment for rendering EPG data may be implemented using any number of programming techniques and may be implemented in local computing systems or in distributed computing systems where tasks are performed by remote processing devices that are linked through various communications networks based on any number of communication protocols. In such a distributed computing system, application modules may be located in both local and remote computer storage media including memory storage devices. The method illustrated in FIG. 7 is described below with reference to components of the example computer system for implementing a three-dimensional television viewing environment that is illustrated in FIG. 5 and more particularly with reference to the exemplary components of client device <b>502</b> as illustrated in FIG. 6.

P-0051[0051] At block <b>702</b>, client device <b>502</b> receives electronic program guide data to be rendered in a three-dimensional viewing environment. For example, tuner <b>620</b> receives electronic program guide data from a broadcast network.

P-0052[0052] At block <b>704</b>, client device <b>502</b> defines multiple two-dimensional areas within a rendered three-dimensional environment. As shown in FIG. 1, areas <b>104</b>, <b>106</b>, <b>108</b>, and <b>110</b> are multiple two-dimensional areas defined within a three-dimensional environment <b>100</b>. Furthermore, the multiple two-dimensional areas can be any size and defined on any plane within a three-dimensional area.

P-0053[0053] At block <b>706</b>, client device <b>502</b> associates portions of the received EPG data with the multiple two-dimensional areas. For example, the received EPG data may be associated with multiple categories, and each category then associated with a different two-dimensional area.

P-0054[0054] At block <b>708</b>, client device <b>502</b> presents a portion of the rendered three-dimensional environment for display to a user. Because the three-dimensional television viewing environment is rendered using a display device <b>206</b>, only a portion of the three-dimensional environment can be displayed at a time. As illustrated and described with reference to FIG. 1, the portion of the three-dimensional environment that is displayed is based on a virtual location and viewing direction <b>102</b> of a viewer within the three-dimensional environment. As the virtual location and viewing direction of a viewer moves, the portion of the three-dimensional environment that is displayed also changes.

P-0055[0055] At block <b>710</b> client device <b>502</b> determines whether or not a navigational input is being received. For example, a viewer submits navigational input to client device <b>502</b> using controller <b>504</b>. The navigational input indicates how the viewer wishes to move the virtual location and viewing direction of the viewer within the three-dimensional environment. If the client device receives navigational input (the “Yes” branch from block <b>710</b>), then the method continues a block <b>712</b>. Otherwise (the “No” branch from block <b>710</b>), the method continues presenting a portion of the three-dimensional environment as described with reference to block <b>708</b>.

P-0056[0056] At block <b>712</b> client device presents a different portion of the three-dimensional environment for display to the user based on the received navigational input. For example, if the received navigational input indicates rotating to the right, then a portion of the three-dimensional environment that is to the right of the currently rendered portion is presented for display to the viewer.

Conclusion

P-0057[0057] Although the systems and methods have been described in language specific to structural features and/or methodological steps, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific features or steps described. Rather, the specific features and steps are disclosed as preferred forms of implementing the claimed invention.