Method for object identification and sensing in a bounded interaction space

• US 20060149495A1
• Filed: 12/21/2005
• Published: 07/06/2006
• Est. Priority Date: 01/05/2005
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Davenport, Glorianna, Mazalek, Alexandra
• Granted Patent: US 7,474,983 B2
• Time in Patent Office: Days
• US Class Current: 702/150
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: G06F 3/0433 in which the acoustic waves are either generated by a movable member and propagated within a surface layer or propagated within a surface layer and captured by a movable member

Abstract

An interactive media table that includes a tabletop that supports of plurality of movable objects each of which is identified by a unique identification code and each of which can be moved from place to place on said tabletop surface by one or more media table users. A display unit produces a visual image on the surface of the tabletop surface and a position tracking system determines the current positions of each of said movable objects by transmitting timed acoustic signals to each movable object, sensing the timing of arrival of these signals using an acoustic pickup on each object, and estimating the location of the object by triangulation. An infrared communications network exchanges timing information, commands and data between the objects and a controller which provides an API to a personal computer which executes an application program that controls the display.

Claims

1. Apparatus for determining the position of a movable object in a detection region comprising, in combination:

at least two spaced apart acoustic signal transmitters located at predetermined positions relative to said detection region each of which emits a sequence of timed acoustic signals that traverse said detection region,

an acoustic signal sensor carried by said movable object for detecting the times of arrival of said acoustic signals at said movable object, and

a data processor for calculating said position of said movable object from said times of arrival.

2. The apparatus for determining the position of a movable object as set forth in claim 1 wherein said detection region is adjacent a surface of a solid through which said timed acoustic signals propagate.

3. The apparatus for determining the position of a movable object as set forth in claim 2 wherein said surface of a solid is substantially horizontal and forms a tabletop supporting said object.

4. The apparatus for determining the position of a movable object as set forth in claim 3 wherein said acoustic signal sensor is carried by said object and is acoustically coupled to said surface to detect said times of arrival of said acoustic signals.

5. The apparatus for determining the position of a movable object as set forth in claim 4 wherein said processor is located remotely from said movable object and wherein said apparatus further comprises a wireless communication link for exchanging data between said movable object and said data processor, said data including data transmitted from said movable object to said processor that are indicative of said times of arrival.

6. The apparatus for determining the position of a movable object as set forth in claim 5 wherein said data further include identification data transmitted from said object to said processor that uniquely identifies said object.

7. The apparatus for determining the position of a movable object as set forth in claim 1 wherein said processor is located remotely from said movable object and wherein said apparatus further comprises a wireless communication link for exchanging data between said movable object and said data processor, said data including information transmitted from said movable object to said data processor that are indicative of said times of arrival.

8. The apparatus for determining the position of a movable object as set forth in claim 7 wherein a manually actuated control is carried by said movable object for receiving input information from a user and wherein said data include said input information transmitted from said movable object to said data processor.

9. The apparatus for determining the position of a movable object as set forth in claim 7 wherein said data further include identification information transmitted from said object to said data processor that uniquely identifies said object.

10. The apparatus for determining the position of a movable object as set forth in claim 9 wherein said data further include start-of-travel timing signals transmitted via said wireless link to said movable object to indicate the time when said acoustic signals are emitted by said acoustic signal transmitters and wherein said data transmitted from said movable object to said processor specify the time-of-flight durations which elapse between said start-of-travel timing signals and said times of arrival.

11. The apparatus for determining the position of a movable object as set forth in claim 7 wherein said wireless communication link is an infrared link.

12. The apparatus for determining the position of a movable object as set forth in claim 7 wherein said wireless communication link is a radio link.

13. The apparatus for determining the position of a movable object as set forth in claim 7 wherein an output device is carried by said movable object for receiving notification signals from said data processor and for rendering said notification signals in a form perceptible to a person positioned to move said movable object.

14. The apparatus for determining the position of a movable object as set forth in claim 13 wherein said output device is a visual indicator.

15. The apparatus for determining the position of a movable object as set forth in claim 13 wherein said output device is a vibratory device for producing audible or haptic signals perceptible to said person.

16. An improvement in a media table of the type consisting of a display device integrated with a tabletop that defines a display surface that supports a plurality of movable objects that can be placed on, and moved from place to place on, said surface by one or more users, said display device producing an image that includes at least one image component that coincides with and moves with a corresponding one of said movable objects, said improvement comprising:

a data processor,

at least two spaced-apart acoustic transmitters, each of which responds to commands from said data processor by emitting timed acoustic signals that propagate through said tabletop to each of said movable objects,

an acoustic signal sensor carried by each given one of said movable objects for detecting the times of arrival of said acoustic signals at said given one of said movable objects,

a wireless communication link coupling said each of said movable objects to said data processor for transmitting data indicative of said times of arrival to said data processor,

a program executable by said data processor for deriving location data from said data indicative of said times of arrival and for generating said image based on said location data.

17. The improvement as set forth in claim 16 wherein said data processor comprises:

a controller connected to said acoustic transmitters for generating said commands and for receiving data indicating said times of arrival from said movable objects, and

a computer coupled to said controller and that executes one or more application program for generating said image, and further executes an application program interface program the generates delivers location data indicating the position of each of said movable objects on said surface to said application program, said location data being derived from said data obtained from said controller indicating said times of arrival.

18. The improvement as set forth in claim 17 wherein each given one of said movable objects stores identification data that uniquely identifies said given one of said objects, wherein said wireless communication link communicates said identification data to said controller, and wherein said application program interface program delivers said location data and said identification data to said application program to separately indicate the position of each of said movable objects.

19. The improvement as set forth in claim 18 wherein each of said movable objects includes an input device for accepting an input signal from one of said users, wherein said input signal is communicated to said application program executing on said computer via said wireless communications link and said application program interface program.

20. The improvement as set forth in claim 18 wherein each of said movable objects includes an output device for producing an output indication perceptible to one or more of said users in response to an output command from said application program executing on said computer and transmitted to said output device via said application program interface program.

21. The improvement as set forth in claim 18 wherein said application program interface program transmits a notification message to said application program when a newly arrived object is placed on said tabletop, said notification message containing identification data stored on said newly arrived object that uniquely identifies said newly arrived object.

22. A media table comprising:

a tabletop display for rendering a visual image presented on a tabletop surface that supports of plurality of movable objects each of which is identified by a unique identification code and each of which can be moved from place to place on said tabletop surface by one or more media table users,

a position tracking system for producing location data indicating the current positions of each of said movable objects, said position tracking system comprising;

a controller,

at least two spaced apart transmitters coupled to said controller for emitting timed acoustic signals that traverse said tabletop surface to each of said objects,

an acoustic signal sensor carried by each given one of said objects for detecting the times of arrival of said acoustic signals at said given one of said objects,

a wireless communications network coupling said controller to each of said objects for receiving information indicative of said times of arrival of said acoustic signals at each of said from each of said objects, and

a position processor for deriving said location data from said information indicative of said times of arrival, and

a display processor coupled to said tabletop display and to said processor for deriving said visual image from said location data and displaying said visual image on said tabletop display.

23. The media table as set forth in claim 22 wherein said position processor first obtains data from said controller indicating the travel times that elapse while an acoustic signals propagates from at least two different ones of said transmitters to a particular object, calculates the distances between said particular object and said different transmitters from said travel times, and then derives the location of said particular object on said tabletop surface by triangulation from said distances.

24. The media table as set forth in claim 23 wherein display processor is implemented by a personal computer that executes an application program for deriving said visual image and wherein said position processor is implemented by said personal computer executing an application program interface program supplies said location data to said application program.

26. The media table as set forth in claim 24 wherein each given one of said movable objects stores identification data that uniquely identifies said given one of said objects, wherein said wireless communication network communicates said identification data to said controller, and wherein said application program interface program delivers said location data and said identification data to said application program to separately indicate the position and identity of each of said movable objects.

27. The media table as set forth in claim 26 wherein a manually actuated control is carried by each of said movable objects for receiving input information from a user, said input information being transmitted from said manually actuated control to said controller via said communications network.

28. A media table comprising:

a tabletop display for rendering a visual image presented on a tabletop display surface that supports of plurality of movable objects, each of said movable objects being identified by a unique identification code and each being movable from place to place on said tabletop display surface by one or more users,

a position tracking system for producing location data for each given one of said movable objects, said location data including the identification code identifying said given one said movable objects and further including position data indicating the current position on said display surface of said given one of said movable objects when said given one of said movable objects is placed on said display surface, and

a display processor responsive to said location data for displaying said visual image on said tabletop display, said visual image including visual components that appear at locations on said tabletop display surface that coincide with and track the locations of corresponding ones of said plurality of moveable objects.

29. A media table as set forth in claim 28 wherein said wherein display processor is implemented by a computer that executes an application program for generating said visual image based on said location data and wherein said position tracking system supplies said location data to said application program via an application program interface program that executes on said computer.

30. A media table as set forth in claim 29 wherein said position tracking program transmits the identification code of said given one of said objects to said application program via said application program interface program when said given one of said movable objects is placed on said display surface.

31. A media table as set forth in claim 28 further including a database for storing attribute information which characterizes each of said plurality of movable objects and wherein said display processor employs the unique identification codes of said corresponding ones of said movable objects to retrieve said attribute information from said database to create said visual image.

32. A media table as set forth in claim 31 wherein said database is located remotely from said display processor and is accessed via a communications network connected between said database and display processor, and wherein said database contains information that is used by a plurality of different media tables.

33. A media table as set forth in claim 32 wherein said visual image includes visual image components representing movable objects which are physically located on other media tables.