Motionless adaptive stereoscopic scene capture with tuneable liquid crystal lenses and stereoscopic auto-focusing methods

Patent metadata

Field	Value
Publication number	US-9161681-B2
Application number	US-201113311377-A
Country	US
Kind code	B2
Filing date	Dec 5, 2011
Priority date	Dec 6, 2010
Publication date	Oct 20, 2015
Grant date	Oct 20, 2015

Abstract

A motionless adaptive focus stereoscopic scene capture apparatus employing tunable liquid crystal lenses is provided. The apparatus includes at least two image sensors preferably fabricated as a monolithic stereo image capture component and at least two corresponding tunable liquid crystal lenses preferably fabricated as a monolithic focus adjustment component. Using a variable focus tunable liquid crystal lens at each aperture stop provides constant magnification focus control. Controlled spatial variance of a spatially variant electric field applied to the liquid crystal of each tunable liquid crystal lens provides optical axis shift enabling registration between stereo images. A controller implements coupled auto-focusing methods employing multiple focus scores derived from at least two camera image sensors and providing multiple tunable liquid crystal lens drive signals for synchronous focus acquisition of a three dimensional scene. Wafer manufacture provides a compact stereoscopic image capture apparatus for endoscopic surgery, optical inspection and entertainment applications.

First claim

What is claimed is:

1. A stereoscopic imaging apparatus for capturing a stereoscopic image of a three dimensional scene, the apparatus comprising:
a plurality of cameras;
a focusing component including a variable optical power tunable liquid crystal lens corresponding to each camera of said plurality of cameras, said focusing component providing stereoscopic focus acquisition by focusing each liquid crystal lens on said scene at a scene distance away from said apparatus; and
at least one of a pair of said tunable liquid crystal lenses including an optical axis orientation adjustment component providing a relative angle of view adjustment between said pair of liquid crystal lenses as a function of said scene distance.

2. An apparatus as claimed in claim 1 , wherein each tunable liquid crystal lens comprises said optical axis orientation adjustment component.

3. An apparatus as claimed in claim 1 , wherein each orientation adjustment component comprises at least one of: an optical axis tilt component, an optical axis shift component, a thermal gradient control system and a microactuator adjusting a spacing between substrates containing said liquid crystal of said lens.

4. An apparatus as claimed in claim 2 , wherein each orientation adjustment component comprises at least one of: an optical axis tilt component, an optical axis shift component, a thermal gradient control system and a microactuator adjusting a spacing between substrates containing said liquid crystal of said lens.

5. An apparatus as claimed in claim 1 , wherein each variable optical power tunable liquid crystal lens has electrical control characteristics, said apparatus further comprising a common tunable liquid crystal electrical control component for said at least two tunable liquid crystal lenses having matched electrical control characteristics.

6. An apparatus as claimed in claim 1 , wherein each camera further comprises an image capture subsystem a fixed distance away from an aperture stop, said liquid crystal lens being located substantially at the aperture stop of said corresponding camera, said image capture subsystem being located at a fixed distance away from said aperture stop and said corresponding liquid crystal lens being located substantially at the aperture stop providing focus adjustment via tunable liquid crystal lens optical power adjustment at fixed magnification.

7. An apparatus as claimed in claim 1 , said apparatus further comprising a common focus control component configured to provide said stereoscopic focus acquisition.

8. An apparatus as claimed in claim 1 , wherein said focusing component further comprises said at least two tunable liquid crystal lenses fabricated as a single unit.

9. An apparatus as claimed in claim 1 , wherein each tunable liquid crystal lens is manufactured employing semiconductor wafer fabrication, said focusing component further comprising said at least two tunable liquid crystal lenses fabricated on a single substrate.

10. An apparatus as claimed in claim 6 , wherein each image capture subsystem further comprises an image sensor.

11. An apparatus as claimed in claim 6 further comprising a focus score source for each image capture subsystem configured to provide a focus score from information obtained from a corresponding image capture subsystem.

12. An apparatus as claimed in claim 1 said apparatus comprising one of an endoscope and a medical endoscope.

13. A stereoscopic imaging apparatus for capturing a stereoscopic image of a three dimensional scene, the apparatus comprising:
a plurality of cameras;
a focusing component including a variable optical power tunable liquid crystal lens corresponding to each camera of said plurality of cameras;
a common focus control component configured to provide stereoscopic focus acquisition by focusing each liquid crystal lens on said scene at a scene distance away from said apparatus: and
an optical axis orientation adjustment component associated with at least one of a pair of said tunable liquid crystal lenses, said optical axis orientation adjustment component providing a relative angle of view adjustment between said pair of liquid crystal lenses as a function of said scene distance.

14. An apparatus as claimed in claim 13 , wherein each camera further comprises an image capture subsystem a fixed distance away from the aperture stop, said liquid crystal lens being located substantially at the aperture stop of said corresponding camera, said image capture subsystem being located at a fixed distance away from said aperture stop and said corresponding liquid crystal lens being located substantially at the aperture stop providing focus adjustment via tunable liquid crystal lens optical power adjustment at fixed magnification.

15. An apparatus as claimed in claim 13 , wherein each tunable liquid crystal lens comprises said optical axis orientation adjustment component.

16. An apparatus as claimed in claim 13 , wherein each orientation adjustment component comprises at least one of: an optical axis tilt component, an optical axis shift component, a thermal gradient control system and a microactuator adjusting a spacing between substrates containing said liquid crystal of said lens.

17. An apparatus as claimed in claim 15 , wherein each orientation adjustment component comprises at least one of: an optical axis tilt component, an optical axis shift component, a thermal gradient control system and a microactuator adjusting a spacing between substrates containing said liquid crystal of said lens.

18. An apparatus as claimed in claim 13 , wherein each variable optical power tunable liquid crystal lens has electrical control characteristics, said apparatus further comprising a common tunable liquid crystal electrical control component for said at least two tunable liquid crystal lenses having matched electrical control characteristics.

19. An apparatus as claimed in claim 13 , wherein said focus control component further comprises said at least two tunable liquid crystal lenses fabricated as a single unit.

20. An apparatus as claimed in claim 13 , wherein each tunable liquid crystal lens is manufactured employing semiconductor wafer fabrication, said focusing component further comprising said at least two tunable liquid crystal lenses fabricated on a single substrate.

21. An apparatus as claimed in claim 14 , wherein each image capture subsystem further comprises an image sensor.

22. An apparatus as claimed in claim 14 further comprising a focus score source for each image capture subsystem configured to provide a focus score from information obtained from a corresponding image capture subsystem.

23. An apparatus as claimed in claim 13 said apparatus comprising one of an endoscope and a medical endoscope.

24. A method for acquiring a stereoscopic image employing an endoscope having a stereoscopic imaging system, the method comprising:
performing image registration between a plurality of acquired images by making a relative angle of view adjustment between a pair of liquid crystal lenses as a function of a scene distance, at least one of said pair of tunable liquid crystal lenses including an optical axis orientation adjustment component;
focusing multiple channels at said scene distance; and
acquiring a stereoscopic image set.

25. A method as claimed in claim 24 further comprising employing eye tracking to select a region of interest in at least one acquired image for i

Assignees

• Galstian Tigran
• Clark Peter P
• Venkatraman Suresh
• Lensvector Inc

Inventors

• Galstian Tigran
• Clark Peter P
• Venkatraman Suresh

Classifications

• H04N13/243

  using three or more two-dimensional [2D] image sensors · CPC title

• A61B1/00193 Primary

  adapted for stereoscopic vision · CPC title

• G02B3/14

  of variable focal length · CPC title

• H04N13/239

  using two two-dimensional [2D] image sensors having a relative position equal to or related to the interocular distance (H04N13/243 takes precedence) · CPC title

• A61B1/044

  for absorption imaging · CPC title