TUNABLE SPECTRAL ILLUMINATOR FOR CAMERA

• US 20200132277A1
• Filed: 11/12/2019
• Published: 04/30/2020
• Est. Priority Date: 10/31/2018
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: AKKAYA, Onur Can, ORTIZ EGEA, Sergio, BAMJI, Cyrus Soli
• Granted Patent: US 10,982,836 B2
• Time in Patent Office: Days
• CPC Class Codes: F21V 14/003 by interposition of elements with electrically controlled variable light transmissivity, e.g. liquid crystal elements or electrochromic devices
• CPC Class Codes: F21V 5/007 Array of lenses or refractors for a cluster of light sources, e.g. for arrangement of multiple light sources in one plane combination of two or more refractors F21V5/008
• CPC Class Codes: F21V 7/22 characterised by materials, surface treatments or coatings, e.g. dichroic reflectors
• CPC Class Codes: F21V 9/40 with provision for controlling spectral properties, e.g. colour, or intensity
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H04N 23/125 Colour sequential image capture, e.g. using a colour wheel
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 5/30 Transforming light or analogous information into electric information scanning details H04N3/00; cameras or camera modules comprising electronic image sensors, or control thereof H04N23/00; circuitry of solid-state image sensors [SSIS] or control thereof H04N25/00

Abstract

A camera includes one or more spectral illuminators, a tunable optical filter optically intermediate the one or more spectral illuminators and a scene, and a sensor array. The one or more spectral illuminators are configured to emit active spectral light. The tunable optical filter is dynamically adjustable to change a selected sub-band of the active spectral light that illuminates the scene. The sensor array includes a plurality of sensors each configured to measure spectral light reflected from the scene in the selected sub-band.

Claims

1. A camera comprising:

a plurality of spectral illuminators each configured to emit active spectral light having an illumination sub-band, wherein one or more of the plurality of spectral illuminators emit active spectral light having a different illumination sub-band than at least one or more other of the plurality of spectral illuminators;

a tunable optical filter optically intermediate the one or more spectral illuminators and a scene, the tunable optical filter dynamically adjustable to change a selected sub-band of the active spectral light that illuminates the scene;

a sensor array including a plurality of sensors; and

a spectral controller machine configured to;

dynamically adjust the tunable optical filter to selectively transmit a selected sub-band of the active spectral light to illuminate the scene,

for at least one spectral illuminator, activate the spectral illuminator if the spectral illuminator is configured to emit active spectral light having an illumination sub-band that at least partially overlaps the selected sub-band, and

address the sensors of the sensor array to measure active spectral light reflected from the scene in the selected sub-band.

2. The camera of claim 1, further comprising an array of collimating lenses optically intermediate the plurality of spectral illuminators and the tunable optical filter, the array of collimating lenses configured to collimate the active spectral light emitted by the plurality of spectral illuminators, and wherein the tunable optical filter receives substantially collimated active spectral light from the array of collimating lenses.

3. The camera of claim 1, further comprising a plurality of dichroic reflectors positioned optically intermediate the plurality of spectral illuminators and the tunable optical filter.

4. The camera of claim 3, wherein each of the plurality of dichroic reflectors is arranged to receive active spectral light from a spectral illuminator of the plurality of spectral illuminators, and wherein the plurality of dichroic reflectors are collectively arranged to optically combine active spectral light collectively received by the plurality of dichroic reflectors.

5. The camera of claim 4, wherein at least one of the plurality of dichroic reflectors reflects active spectral light received from a spectral illuminator of the plurality of spectral illuminators and transmits active spectral light received and reflected by another of the plurality of dichroic filters.

6. The camera of claim 5, wherein each dichroic reflector is configured to transmit light having a wavelength longer than a threshold wavelength and reflect light having a wavelength that is shorter than the threshold wavelength.

7. The camera of claim 5, wherein the plurality of dichroic reflectors are collectively arranged to direct the combined active spectral light towards the tunable optical filter.

8. The camera of claim 7, further comprising a folding mirror optically intermediate the plurality of dichroic reflectors and the tunable optical filter, the folding mirror configured to reflect the optically combined active spectral light en route to the tunable optical filter.

9. The camera of claim 1, further comprising a macro collimating lens operatively intermediate the plurality of spectral illuminators and the tunable optical filter, the macro collimating lens configured to collimate the active spectral light emitted by the plurality of spectral illuminators, and wherein the tunable optical filter receives substantially collimated active spectral light from the macro collimating lens.

10. The camera of claim 1, wherein the plurality of spectral illuminators include a plurality of light emitting diodes arranged in an array.

11. The camera of claim 1, wherein the plurality of spectral illuminators include a plurality of discrete light emitting diodes.

12. The camera of claim 1, wherein the tunable optical filter includes a Fabry-Perot interferometer comprising an optical cavity formed between a first reflective surface and a second reflective surface.

13. The camera of claim 12, wherein the Fabry-Perot interferometer is configured to change the sub-band of active spectral light that illuminates the scene by adjusting a length of the optical cavity.

14. The camera of claim 12, wherein the optical cavity includes liquid crystal material, and wherein the Fabry-Perot interferometer is configured to change the sub-band of active spectral light that illuminates the scene by changing a refractive index of the liquid crystal material.

15. The camera of claim 14, wherein the liquid crystal material is polarization sensitive, and wherein the one or more spectral illuminators are configured to emit active spectral light with a polarization that substantially matches a polarization of the liquid crystal material.

16. The camera of claim 1, wherein the tunable optical filter is configured to substantially block active spectral light outside of the selected sub-band.

17. A camera comprising:

a plurality of spectral illuminators each configured to emit active spectral light having an illumination sub-band, wherein one or more of the plurality of spectral illuminators emit active spectral light having a different illumination sub-band than at least one or more other of the plurality of spectral illuminators;

a tunable optical filter optically intermediate the one or more spectral illuminators and a scene, the tunable optical filter dynamically adjustable to change a selected sub-band of the active spectral light that illuminates the scene;

one or more optical elements optically intermediate the plurality of spectral illuminators and the tunable optical filter, the one or more optical elements each configured to direct the active spectral light emitted by the plurality of spectral illuminators towards the tunable optical filter;

a sensor array including a plurality of sensors; and

a spectral controller machine configured to;

dynamically adjust the tunable optical filter to selectively transmit a selected sub-band of the active spectral light to illuminate the scene,

for at least one spectral illuminator, activate the spectral illuminator if the spectral illuminator is configured to emit active spectral light having an illumination sub-band that at least partially overlaps the selected sub-band, and

address the sensors of the sensor array to measure active spectral light reflected from the scene in the selected sub-band.

18. The camera of claim 17, wherein the one or more optical components includes a plurality of dichroic reflectors, wherein each of the plurality of dichroic reflectors is arranged to receive active spectral light from a spectral illuminator of the plurality of spectral illuminators, and wherein the plurality of dichroic reflectors are collectively arranged to optically combine active spectral light collectively received by the plurality of dichroic reflectors.

19. The camera of claim 18, wherein at least one of the plurality of dichroic reflectors reflects active spectral light received from a spectral illuminator of the plurality of spectral illuminators and transmits active spectral light received and reflected by another of the plurality of dichroic filters.

20. A camera comprising:

a plurality of spectral illuminators each configured to emit active spectral light having an illumination sub-band, wherein one or more of the plurality of spectral illuminators emit active spectral light having a different illumination sub-band than at least one or more other of the plurality of spectral illuminators;

a Fabry-Perot interferometer optically intermediate the plurality of spectral illuminators and a scene, the Fabry-Perot interferometer dynamically adjustable to change a selected sub-band of the active spectral light that illuminates the scene;

one or more optical elements optically intermediate the plurality of spectral illuminators and the Fabry-Perot interferometer, the one or more optical elements each configured to direct the active spectral light emitted from by the plurality of spectral illuminators towards the Fabry-Perot interferometer; and

a sensor array including a plurality of sensors each configured to measure active spectral light reflected from the scene in the selected sub-band.