Tracking system using fixed optical radiators
Apparatus for tracking an object ( 12 A, 12 B, 12 C) including radiator modules ( 16 A, 16 B, 16 C), disposed in an array of known locations adjoining a region ( 13 ) in which the object moves; each module includes at least one emitter ( 44, 46, 48 ) which emits a respective color selected from among a first plurality of colors. The apparatus includes a controller ( 32 ), which drives the at least one emitter to emit during a respective time slot, selected from among a second plurality of time slots during which the modules may emit. The apparatus also includes a location unit ( 22 ), fixed to the object and including at least one camera ( 72 ), which captures a sequence of electronic images containing some of the locations of the modules. The apparatus further includes a processing unit ( 26 ), which processes the electronic images to determine, responsively to the colors emitted by the modules and the time slots in which the colors are emitted, a location of the object.
1. Apparatus for tracking an object, comprising:
a. a multiplicity of optical radiator modules, disposed in an array of known locations adjoining a region in which the object is to move, each module comprising:
i. at least one optical emitter, which is structured to emit optical radiation of a respective color, selected from among a first plurality of colors emittable by the modules;
ii. and a controller, which is coupled to drive the at least one optical emitter to emit the optical radiation during a respective time slot, selected from among a second plurality of time slots during which the modules may emit the optical radiation, such that the respective color and the respective time slot form a unique combination for each of the modules;
b. an optical location unit, structured to be fixed to the object and comprising at least one camera, which is arranged to capture a sequence of electronic images containing at least some of the locations of the modules;
c. and a processing unit, which is configured to process the electronic images in the sequence in order to determine, responsively to the colors of the optical radiation emitted by the modules and the time slots in which the optical radiation is emitted, a location of the object.
2. The apparatus according to claim 1 , wherein the location of the object comprises a locus of possible locations of the object, and wherein the processing unit is configured to determine the locus in response to the at least some locations of the modules.
3. The apparatus according to claim 1 , wherein the at least some of the locations of the modules comprises two locations of the modules, and wherein the processing unit is configured to apply one or more limiting regions for the object so as to determine the location of the object as a unique location.
4. The apparatus according to claim 1 , wherein the optical location unit comprises a microprocessor which is programmed to perform an initial processing of the sequence of electronic images so as to determine pixel coordinates of the at least some locations of the modules, wherein the optical location unit is programmed to convey the pixel coordinates to the processing unit, and wherein the processing unit is programmed to process the pixel coordinates to determine the location of the object.
5. The apparatus according to claim 1 , wherein for each module, the at least one optical emitter comprises at least first and second optical emitters of different, first and second colors, and wherein the controller is configurable to select one of the first and second colors to be emitted by the module.
6. The apparatus according to claim 1 , wherein the region comprises at least one of a ceiling and at least one wall, and wherein the multiplicity of modules are fixed to at least one of the ceiling and the at least one wall, and are configured to radiate the optical radiation into the region.
7. The apparatus according to claim 1 , wherein the at least one optical emitter comprises at least one light-emitting diode (LED).
8. The apparatus according to claim 1 , wherein the processing unit is coupled to a memory, and wherein the processing unit is configured to create a tracking database in the memory containing records of the location of the object in the region.
9. The apparatus according to claim 1 , wherein the optical location unit is fixed to the object so that the at least one camera is in a predetermined direction on capturing the sequence of electronic images.
10. The apparatus according to claim 1 , wherein the processing unit transmits signals to the optical radiator modules which determine the respective color and the respective time slot of each of the modules, and which synchronize the time slots.
11. The apparatus according to claim 10 , wherein the processing unit transmits the signals to the optical location unit so as to synchronize the time slots with the sequence of electronic images.
12. The apparatus according to claim 10 , wherein the signals comprise a radio frequency (RF) signal.
13. The apparatus according to claim 10 , wherein the signals comprise a Global Positioning System (GPS) synchronization beacon.
14. The apparatus according to claim 1 , wherein the at least some of the locations of the modules comprises three locations of the modules, and wherein the location of the object comprises a unique location.
15. The apparatus according to claim 14 , wherein the unique location comprises a unique intersection of three loci of possible locations of the object, and wherein the processing unit is configured to determine the three loci in response to the three locations of the modules.
16. A method for tracking an object, comprising:
a. disposing a multiplicity of optical radiator modules in an array of known locations adjoining a region in which the object is to move, each module comprising: at least one optical emitter, which is structured to emit optical radiation of a respective color, selected from among a first plurality of colors emittable by the modules, and a controller, which is coupled to drive the at least one optical emitter to emit the optical radiation during a respective time slot, selected from among a second plurality of time slots during which the modules may emit the optical radiation, such that the respective color and the respective time slot form a unique combination for each of the modules;
b. fixing an optical location unit comprising at least one camera to the object;
c. capturing from the at least one camera a sequence of electronic images containing at least some of the locations of the modules; and,
d. processing the electronic images in the sequence in order to determine, responsively to the colors of the optical radiation emitted by the modules and the time slots in which the optical radiation is emitted, a location of the object.
17. The method according to claim 16 , wherein the location of the object comprises a locus of possible locations of the object, and determining the location of the object comprises determining the locus in response to the at least some locations of the modules.
18. The method according to claim 16 , wherein the at least some of the locations of the modules comprises two locations of the modules, and comprising applying one or more limiting regions for the object so as to determine the location of the object as a unique location.
19. The method according to claim 16 , wherein the optical location unit comprises a microprocessor which performs an initial processing of the sequence of electronic images so as to determine pixel coordinates of the at least some locations of the modules, and wherein processing the electronic images comprises processing the pixel coordinates to determine the location of the object.
20. The method according to claim 16 , wherein for each module, the at least one optical emitter comprises at least first and second optical emitters of different, first and second colors, and wherein the controller is configurable to select one of the first and second colors to be emitted by the module.
21. The method according to claim 16 , wherein the region comprises at least one of a ceiling and at least one wall, and wherein the multiplicity of modules are fixed to at least one of the ceiling and the at least one wall, and are configured to radiate the optical radiation into the region.
22. The method according to claim 16 , wherein the at least one optical emitter comprises at least one light-emitting diode (LED).
23. The method according to claims 16 , wherein processing the electronic images comprises creating a tracking database in a memory containing records of the location of the object in the region.
24. The method according to claim 16 , wherein fixing the optical location unit to the object comprises fixing the unit so that the at least one camera is in a predetermined direction on capturing the sequence of electronic images.
25. The method according to claim 16 , further comprising transmitting signals to the optical radiator modules which determine the respective color and the respective time slot of each of the modules, and which synchronize the time slots.
26. The method according to claim 25 , and comprising transmitting the signals to the optical location unit so as to synchronize the time slots with the sequence of electronic images.
27. The method according to claim 25 , wherein the signals comprise a radio frequency (RF) signal.
28. The method according to claim 25 , wherein the signals comprise a Global Positioning System (GPS) synchronization beacon.
29. The method according to claim 16 , wherein the at least some of the locations of the modules comprises three locations of the modules, and wherein the location of the object comprises a unique location.
30. The method according to claim 29 , wherein the unique location comprises a unique intersection of three loci of possible locations of the object, and comprising determining the three loci in response to the three locations of the modules.