Methods and apparatus for bokeh codes

• US 20110017826A1
• Filed: 07/16/2010
• Published: 01/27/2011
• Est. Priority Date: 07/23/2009
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Smithwick, Quinn, Hiura, Shinsaku, Mohan, Ankit, Woo, Grace, Raskar, Ramesh
• Granted Patent: US 8,366,003 B2
• Time in Patent Office: Days
• US Class Current: 235/462.11
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B

Abstract

In an illustrative implementation of this invention, an optical pattern that encodes binary data is printed on a transparency. For example, the pattern may comprise data matrix codes. A lenslet is placed at a distance equal to its focal length from the optical pattern, and thus collimates light from the optical pattern. The collimated light travels to a conventional camera. For example, the camera may be meters distant. The camera takes a photograph of the optical pattern at a time that the camera is not focused on the scene that it is imaging, but instead is focused at infinity. Because the light is collimated, however, a focused image is captured at the camera'"'"'s focal plane. The binary data in the pattern may include information regarding the object to which the optical pattern is affixed and information from which the camera'"'"'s pose may be calculated.

Claims

1. A system comprising, in combination:

an optical pattern in or on an object, and

apparatus adapted for altering the direction of light rays from said pattern in such a way that

binary data encoded in the spatial domain of said pattern is encoded in angular variation of said light rays after said alteration,

said light rays travel to a camera, and

a substantially focused image of at least a part of said pattern is captured at the sensor plane of said camera at a time that said camera is not focused on said object,

wherein said system is separate from and not part of a unified structure with said camera.

2. The system of claim 1, wherein said apparatus for altering the direction of light comprises at least one lens.

3. A system comprising, in combination:

an optical pattern in or on an object, and

apparatus adapted for altering the direction of light rays from said pattern in such a way that

said light rays travel to a camera that is not focused on said object, and

a substantially focused image of at least a part of said pattern is captured at the sensor plane of said camera,

wherein said system is separate from and not part of a unified structure with said camera.

4. The system of claim 3, wherein said apparatus is configured for collimating light from said object in such a way that said light travels to said camera for imaging of at least part of said optical pattern while said camera is focused at infinity.

5. The system of claim 3, wherein said apparatus for altering the direction of light comprises at least one lens.

6. The system of claim 5, wherein said optical pattern encodes binary data.

7. The system of claim 5, wherein said binary data includes information for error correction.

8. The system of claim 5, wherein at least one portion of said binary data indicates the spatial position of said portion relative to said pattern.

9. The system of claim 5, wherein said optical pattern comprises data matrix codes.

10. The system of claim 5, wherein said binary data includes data regarding the position or identity of a person or thing other than said apparatus.

11. The system of claim 3, wherein said apparatus is adapted to be carried by a human or to be affixed to items carried or worn by said human.

12. The system of claim 3, wherein said optical pattern is backlit at the time said camera images said pattern.

13. The system of claim 3, further comprising at least one radio frequency identification tag that is directly or indirectly affixed, or adapted to be directly or indirectly affixed, to said object.

14. The system of claim 3, wherein said apparatus is affixed or adapted to be affixed to an automobile or other vehicle.

15. The system of claim 3, wherein said object is adapted to display said optical pattern in such a way that said pattern changes over time.

16. Apparatus comprising a camera adapted for capturing a substantially focused image of at least part of an optical pattern while such camera is not focused at the depth of said optical pattern, wherein:

said optical pattern is in or on an object,

said optical pattern encodes binary data,

light from said optical pattern passes through an optical system that alters the direction of said light before said light strikes said camera, and

both said object and said optical system are separate from, and not part of a unified structure with, said camera.

17. The apparatus of claim 16, wherein said camera is adapted for imaging said optical pattern while such camera is focused substantially at infinity.

18. The apparatus of claim 16, wherein said camera is adapted for outputting data indicative of said image captured by said camera, for transmission to an onboard or remote computer for decoding of said binary data.

19. The apparatus of claim 16, further comprising a digital processor for

decoding bytes of said binary data, which bytes encode the position of said bytes in said optical pattern, and

based on the positional data so decoded, calculating the camera'"'"'s pose relative to the optical axis of said optical system.

20. The apparatus of claim 16, wherein said camera, alone or together with at least one other camera, is adapted for imaging a plurality of said optical patterns in or on objects worn by or affixed to a plurality of persons.

21. The apparatus of claim 16, further comprising a digital processor for:

decoding said binary data, and

outputting instructions regarding audio or visual stimuli produced by at least one transducer, in such a way that said instructions depend at least in part on said decoded data.

22. The system of claim 16, wherein said optical system comprises at least one lens.

23. A method comprising using a camera to capture a focused image of a visual pattern, wherein

said visual pattern is in or on an object,

said pattern encodes binary data,

an optical system alters the direction of light from said pattern before said light strikes said camera,

said alteration of direction causes said captured image to be focused even though said camera is not focused on said pattern at the time said image is captured, and

both said object and said optical system are separate from, and not part of a unified structure with, said camera.

24. The method of claim 23, wherein said optical system comprises at least one lens.

25. The method of claim 23, wherein said camera is focused substantially at infinity while it images said visual pattern.