CAPTURING AN IMAGE OF A SCENE

• US 20190328209A1
• Filed: 12/14/2017
• Published: 10/31/2019
• Est. Priority Date: 12/16/2016
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Springer, Paul, Emmerich, Thimo, Facius, Zoltan
• Granted Patent: US 11,510,548 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 1/00009 of image signals during a use of endoscope
• CPC Class Codes: A61B 1/000095 for image enhancement
• CPC Class Codes: A61B 1/00186 with imaging filters
• CPC Class Codes: A61B 1/00188 with focusing or zooming features
• CPC Class Codes: A61B 1/045 Control thereof
• CPC Class Codes: G02B 23/2484 Arrangements in relation to a camera or imaging device processing or control of video signals generated by an endoscope H04N23/60, H04N23/70
• 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 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001

Abstract

An imaging device for use with an endoscope, the imaging device comprising: a lens arrangement operable to receive light from a scene captured by the endoscope and to form an image of the scene using the received light; an image sensor operable to capture the image of the scene formed by the lens arrangement; a birefringent device positioned along an optical path between the endoscope and the image sensor, wherein the birefringent device comprises birefringent material arranged in a plurality of concentric rings, and wherein the birefringent material of each of the concentric rings is configured such that the polarisation directions of an ordinary ray and an extraordinary ray of light from the scene which travels through the birefringent material are different for at least two of the plurality of concentric rings; and an image processor operable to process the captured image to generate an output image.

Claims

1. An imaging device for use with an endoscope, the imaging device comprising:

a lens arrangement operable to receive light from a scene captured by the endoscope and to form an image of the scene using the received light;

an image sensor operable to capture the image of the scene formed by the lens arrangement;

a birefringent device positioned along an optical path between the endoscope and the image sensor, wherein the birefringent device comprises birefringent material arranged in a plurality of concentric rings, and wherein the birefringent material of each of the concentric rings is configured such that the polarisation directions of an ordinary ray and an extraordinary ray of light from the scene which travels through the birefringent material are different for at least two of the plurality of concentric rings; and

an image processor operable to process the captured image to generate an output image.

2. The imaging device according to claim 1, wherein the polarisation directions of the ordinary ray and the extraordinary ray differ by 90°

for the at least two of the plurality of concentric rings.

3. The imaging device according to claim 2, wherein the birefringent device comprises a central circular portion which is concentric with each of the concentric rings and which has a diameter such that the central circular portion is within an inner diameter of each of the concentric rings, wherein a birefringent material of the central circular portion is configured such that the polarisation directions of the ordinary ray and the extraordinary ray for the central circular portion are different to the polarisation directions of the ordinary ray and the extraordinary ray for each of the plurality of concentric rings.

4. The imaging device according to claim 3, wherein the polarisation directions of the ordinary ray and the extraordinary ray for the central circular portion differ by 45°

to the polarisation directions of the ordinary ray and the extraordinary ray for each of the plurality of concentric rings.

5. The imaging device according to claim 3, wherein:

an inner diameter and outer diameter of each of the plurality of concentric rings and a diameter of the central circular portion are configured such that;

light captured by a first endoscope with a larger diameter is masked by the central circular portion and the plurality of concentric rings; and

light captured by a second endoscope with a smaller diameter is masked by the central circular portion only.

6. The imaging device according to claim 1, wherein the birefringent device is positioned along an optical path between the endoscope and the lens arrangement.

7. The imaging device according to claim 1, wherein the birefringent device is positioned at a pupil plane of the lens arrangement.

8. The imaging device according to claim 1, wherein the image processor is operable to apply processing to the captured image so as to remove blur from the captured image, the blur being constant over a predetermined object distance range in the captured image in accordance with one or more characteristics of the birefringent device.

9. The imaging device according to claim 8, wherein the blur is defined by an in-focus point spread function and the processing comprises applying an inverse of the in-focus point spread function to the captured image.

10. The imaging device according to claim 1, wherein the endoscope is a medical endoscope.

11. A system comprising an optical device according to claim 1 and an endoscope configured to captured light from the scene for use by the lens arrangement of the imaging device in forming an image of the scene on the image sensor of the imaging device.

12. A birefringent device for use with an imaging device according to claim 1, the birefringent device being positionable along an optical path between an endoscope for capturing light from a scene and an image sensor of the imaging device on which an image of the scene is formed using the captured light, wherein the birefringent device comprises birefringent material arranged in a plurality of concentric rings, and wherein the birefringent material of each of the concentric rings is configured such that the polarisation directions of an ordinary ray and an extraordinary ray of light from the scene which travels through the birefringent material are different for at least two of the plurality of concentric rings;

wherein;

the polarisation directions of the ordinary ray and the extraordinary ray differ by 90°

for the at least two of the plurality of concentric rings; and

the birefringent device comprises a central circular portion which is concentric with each of the concentric rings and which has a diameter such that the central circular portion is within an inner diameter of each of the concentric rings, wherein the birefringent material of the central circular portion is configured such that the polarisation directions of the ordinary ray and the extraordinary ray for the central circular portion are different to the directions of the polarisation directions of the ordinary ray and the extraordinary ray for each of the plurality of concentric rings.

13. A birefringent device according to claim 12, wherein the polarisation directions of the ordinary ray and the extraordinary ray for the central circular portion differ by 45°

to the polarisation directions of the ordinary ray and the extraordinary ray for each of the plurality of concentric rings.

14. A birefringent device according to claim 10, wherein:

an inner diameter and outer diameter of each of the plurality of concentric rings and a diameter of the central circular portion are configured such that;

light captured by a first endoscope with a larger diameter is masked by the central circular portion and the plurality of concentric rings; and

light captured by a second endoscope with a smaller diameter is masked by the central circular portion only.

15. A method of capturing an image of a scene, the method comprising:

capturing an image of the scene using an image sensor, the image of the scene being formed at the image sensor by a lens arrangement using light from the scene captured by an endoscope, wherein a birefringent device is positioned along an optical path between the endoscope and the image sensor, wherein the birefringent device comprises birefringent material arranged in a plurality of concentric rings, and wherein the birefringent material of each of the concentric rings is configured such that the polarisation directions of an ordinary ray and an extraordinary ray of light from the scene which travels through the birefringent material are different for at least two of the plurality of concentric rings; and

processing the captured image to generate an output image.

16. A recording medium storing a computer program for controlling a computer to perform a method according to claim 15.