Image Capture with Digital Light Path Length Modulation

• US 20180048814A1
• Filed: 01/04/2017
• Published: 02/15/2018
• Est. Priority Date: 08/12/2016
• Status: Active Grant

• Current Assignee: Avegant Corp
• Original Assignee: Avegant Corp
• Inventors: Evans, Allan Thomas, Dewald, D. Scott, Gross, Andrew John
• Granted Patent: US 10,057,488 B2
• Time in Patent Office: Days
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G02B 2207/117 Adjustment of the optical path length
• CPC Class Codes: G02B 27/0075 with means for altering, e.g. increasing, the depth of field or depth of focus
• CPC Class Codes: G02B 27/28 for polarising used in stereoscopes G02B30/25
• CPC Class Codes: G02B 27/285 comprising arrays of elements, e.g. microprisms
• CPC Class Codes: G02B 27/40 Optical focusing aids
• CPC Class Codes: G06F 3/03 Arrangements for converting the position or the displacement of a member into a coded form
• CPC Class Codes: G06T 2207/10148 Varying focus
• CPC Class Codes: G06T 2207/20221 Image fusion; Image merging
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 5/73 Deblurring; Sharpening
• CPC Class Codes: H04N 23/54 Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 23/60 Control of cameras or camera modules
• CPC Class Codes: H04N 23/63 by using electronic viewfinders
• CPC Class Codes: H04N 23/676 Bracketing for image capture at varying focusing conditions
• CPC Class Codes: H04N 23/698 for achieving an enlarged field of view, e.g. panoramic image capture
• CPC Class Codes: H04N 23/80 Camera processing pipelines; Components thereof
• CPC Class Codes: H04N 5/2621 Cameras specially adapted for the electronic generation of special effects during image pickup, e.g. digital cameras, camcorders, video cameras having integrated special effects capability

Abstract

An image capture system comprising an optical path length extender (OPLE) to direct the light having a first polarization through a first light path through the OPLE, and to direct the light having a second polarization through a second light path through the OPLE, the first and second light paths having different light path lengths. The image capture system further comprising an image sensor to capture a plurality of image portions at a plurality of focal distances.

Claims

1. An image capture system comprising:

a lens directed at a scene to be captured;

a modulation stack comprising one or more digital light path length modulators, a digital light path length modulator comprising;

a polarization modulator to receive light and to selectively modulate a polarization of the light; and

an optical path length extender (OPLE) to direct the light having a first polarization through a first light path through the OPLE, and to direct the light having a second polarization through a second light path through the OPLE, the first and second light paths having different light path lengths; and

an image sensor to capture a plurality of image portions at a plurality of focal distances, from the data captured by the modulation stack, wherein a number of focal distances depends on the number of the one or more digital light path length modulators.

2. The image capture system of claim 1, wherein the modulation stack adjusts the path length of the light by altering the polarization of the light between the one or more digital light path length modulators to create a plurality of light path lengths associated with the plurality of digital light path length modulators in the modulation stack.

3. The image capture system of claim 1, wherein a farthest virtual object distance is infinity, and the focal distances move in discrete steps.

4. The image capture system of claim 1, further comprising:

a digital correction system to separate simultaneously captured image portions with different focal distances.

5. The image capture system of claim 1, wherein the polarization modulator alters the path length on a time sequential basis, enabling the image sensor to capture a time sequential series of images at a plurality of focal distances.

6. The image capture system of claim 1, further comprising:

an auxiliary control system to enable selection of the plurality of focal distances for the image capture.

7. The image capture system of claim 1, further comprising:

a display system to display the plurality of image portions at the plurality of focal distances.

8. The image capture system of claim 1, further comprising:

a last OPLE in the modulation stack, the last OPLE including a plurality of stripes, to enable simultaneous capture of image elements at two focal distances with the image capture device.

9. The image capture system of claim 1, further comprising:

a camera body including the image sensor and a lens; and

the modulation stack implemented in a camera lens assembly, enabling retrofitting of an existing camera for multi-focal image capture.

10. The image capture system of claim 1, further comprising:

a processor to process captured data from the image sensor, the processor to enable one or more of;

reconstructing the captured data based on one of polarization or wavelength, perform wavelength-based analysis, reconstructing a light field based on two or more images at different focal distances, generating a 3D scan based on a plurality of images at a plurality of focal distances, and creating a multi-focal 360 degree photo.

11. The image capture system of claim 1, wherein the image captured is video, and the system continuously captures video frames at a plurality of focal distances.

12. The image capture system of claim 11, wherein the plurality of focal distances are adjustable during the image capture.

15. The image capture system of claim 1, further comprising:

an auxiliary control system to enable selection of a focal distance for the image capture.

16. The image capture system of claim 15, wherein the auxiliary control system includes content-based focal distance selection to automatically identify one or more focal distances for capture.

13. An image capture system comprising:

a modulation stack comprising one or more digital light path length modulators, a digital light path length modulator comprising;

a polarization modulator to receive light and to selectively modulate a polarization of the light; and

an optical path length extender (OPLE) to direct the light having a first polarization through a first light path through the OPLE, and to direct the light having a second polarization through a second light path through the OPLE, the first and second light paths having different light path lengths; and

an image capture device to capture a plurality of image portions at a plurality of focal distances.

14. The image capture system of claim 13, wherein the polarization modulator alters the path length on a time sequential basis, enabling the image capture device to capture a time sequential series of images at a plurality of focal distances.

17. The image capture system of claim 13, comprising:

a last OPLE in the modulation stack, the last OPLE including a plurality of stripes, to enable simultaneous capture of image elements at two focal distances with the image capture device.

18. The image capture system of claim 13, wherein the modulation stack is implemented in a camera lens assembly, enabling retrofitting of an existing camera for multi-focal image capture.

19. An image capture system comprising:

an image capture sub-system including;

a lens directed at a scene to be captured;

a modulation stack comprising one or more digital light path length modulators, a digital light path length modulator comprising;

a polarization modulator to receive light and to selectively modulate a polarization of the light; and

an optical path length extender (OPLE) to direct the light having a first polarization through a first light path through the OPLE, and to direct the light having a second polarization through a second light path through the OPLE, the first and second light paths having different light path lengths; and

an image sensor to capture a plurality of image portions at a plurality of focal distances, from the data captured by the modulation stack, wherein a number of focal distances depends on the number of the one or more digital light path length modulators;

an auxiliary control system to select the plurality of focal distances; and

a processor to process the captured data, to generate one or more of;

a plurality of images at a plurality of focal distances, or a multi-focal image.

20. The image capture system of claim 19, comprising:

a camera including the image capture subassembly; and

a computer system including the processor, wherein the camera and the computer system are coupled using an I/O system.

21. An optical path length extender (OPLE) comprising:

a plurality of polarization sensitive reflective elements parallel to each other and at an angle of between 20 degrees and 70 degrees to a path of light entering the OPLE, to direct the light having a first polarization through a first light path through the OPLE, and to direct the light having a second polarization through a second light path through the OPLE, the first and second light paths having different light path lengths;

a plurality of light blocking stripes on an entry surface of the OPLE, to block light; and

wherein an output of the OPLE comprises alternating stripes of image data, at a first and a second focal distance.

22. The OPLE of claim 21, wherein the OPLE is used in one of:

an image capture apparatus to capture image data at two focal distances; and

an image display apparatus to display data at two focal distances.

23. An image capture system comprising:

a lens directed at a scene to be captured;

an optical path length extender (OPLE) to direct the light having a first polarization through a first light path through the OPLE, and to direct the light having a second polarization through a second light path through the OPLE, the first and second light paths having different light path lengths; and

an image sensor to capture a plurality of image portions at a plurality of focal distances, from the data captured by the modulation stack.

24. The image capture system of claim 23, further comprising:

a polarizer; and

a digital light path length modulator comprising;

a polarization modulator to receive light and to selectively modulate a polarization of the light; and

the optical path length extender (OPLE) to receive the light from the polarization modulator.

25. The image capture system of claim 23, wherein the OPLE further comprises:

a plurality of polarization sensitive reflective elements parallel to each other and at an angle of between 20 degrees and 70 degrees to a path of light entering the OPLE;

a plurality of light blocking stripes on an entry surface of the OPLE, to block light;

wherein an output of the OPLE comprising alternating stripes of image data, at a first and a second focal distance.