Folded optic array camera using refractive prisms

• US 9,854,182 B2
• Filed: 01/06/2017
• Issued: 12/26/2017
• Est. Priority Date: 06/20/2014
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Georgiev, Todor Georgiev
• Primary Examiner(s): KHAN, USMAN A
• Application Number:
  US15/400,733
• Publication Number:
  US 20170118421A1
• Time in Patent Office: 354 Days
• Field of Search: 348262
• CPC Class Codes: G02B 13/006 at least one element being a compound optical element, e.g. cemented elements
• CPC Class Codes: G02B 13/0065 having a beam-folding prism or mirror
• CPC Class Codes: G02B 13/007 the beam folding prism having at least one curved surface
• CPC Class Codes: G02B 13/06 Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces
• CPC Class Codes: G02B 5/04 Prisms
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G03B 17/17 with reflectors arranged in beam forming the photographic image, e.g. for reducing dimensions of camera
• CPC Class Codes: G03B 37/04 with cameras or projectors providing touching or overlapping fields of view
• CPC Class Codes: G06T 3/4038 Image mosaicing, e.g. composing plane images from plane sub-images
• CPC Class Codes: H04N 23/45 for generating image signals from two or more image sensors being of different type or operating in different modes, e.g. with a CMOS sensor for moving images in combination with a charge-coupled device [CCD] for still images
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 23/698 for achieving an enlarged field of view, e.g. panoramic image capture
• CPC Class Codes: H04N 25/41 Extracting pixel data from a plurality of image sensors simultaneously picking up an image, e.g. for increasing the field of view by combining the outputs of a plurality of sensors
• CPC Class Codes: Y10T 29/49119 Brush
• CPC Class Codes: Y10T 29/49828 Progressively advancing of work assembly station or assembled portion of work

Abstract

Aspects relate to a prism array camera having a wide field of view. For example, the prism array camera can use a central refractive prism, for example with multiple surfaces or facets, to split incoming light comprising the target image into multiple portions for capture by the sensors in the array. The prism can have a refractive index of approximately 1.5 or higher, and can be shaped and positioned to reduce chromatic aberration artifacts and increase the FOV of a sensor. In some examples a negative lens can be incorporated into or attached to a camera-facing surface of the prism to further increase the FOV.

Claims

1. A method of using a prism array camera for capturing an image of a target scene, the prism array camera including a plurality of cameras positioned around a vertical axis of symmetry of the prism array camera, each camera of the plurality of cameras comprising an image sensor and an optical axis positioned at a first angle relative to the vertical axis of symmetry, the prism array camera further including a plurality of prisms with each prism corresponding to one of the plurality of cameras, each prism having a first, second and third surface and configured to direct light received from the target scene toward a corresponding camera, the method comprising:

receiving light from the target scene on the first surfaces of each one of the plurality of prisms, each of the plurality of prisms configured such that the received light propagates into the prism through the first surface; and

in each prism,

reflecting light propagating in said each prism off of the second surface, the second surface positioned such that a plane formed by the second surface bisects the first angle between the optical axis of the corresponding camera and the vertical axis of symmetry, and

propagating the reflected light through the third surface of said each prism, the third surface positioned such that light from the target scene exits said each prism and propagates toward the corresponding camera corresponding to said each prism.

2. The method of claim 1, further comprising, for each camera, receiving the light propagated through the third surface of the corresponding prism at the image sensor of the camera.

3. The method of claim 1, wherein the first surfaces of each of the plurality of prisms are positioned orthogonally to the vertical axis of symmetry of the prism array camera.

4. The method of claim 2, further comprising providing a processor in electronic communication with the plurality of cameras.

5. The method of claim 4, further comprising receiving, by the processor from each of the plurality of cameras, an image generated from the portion of light received by the sensor.

6. The method of claim 5, further comprising combining the image from each of the plurality of cameras into a final image of the target scene.

7. The method of claim 1, wherein each of the plurality of prisms further comprises an apex at a point of intersection between the first surface and the second surface, and wherein the plurality of cameras are configured such that the optical axis of the each camera of the plurality of cameras and the vertical axis of symmetry of the prism array camera system pass through the apex.

8. The method of claim 1, wherein the third surfaces of each of the plurality of prisms are arranged at a second angle relative to the first surface, the second angle having a same angular value as the first angle.

9. The method of claim 1, wherein the third surfaces of each of the plurality of prisms each comprise a negative lens formed in or affixed to the third surface.

10. The method of claim 9, wherein propagating light through the third surface comprises refracting the reflected light through the negative lens.

11. The method of claim 9, further comprising increasing a field of view the corresponding camera by refracting the reflected light through the negative lens.

12. The method of claim 1, further comprising, for each camera of the plurality of cameras, reflecting the light propagated through the third surface of the corresponding prism off of an additional light folding surface positioned between the corresponding prism and an image sensor of the camera.

13. The method of claim 12, further comprising, for each camera of the plurality of cameras, refracting the light propagated through the third surface of the corresponding prism through a lens assembly positioned between the third surface and the additional light folding surface.

14. A method of capturing an image of a target scene with a prism array camera having a plurality of cameras, each camera positioned around a vertical axis of symmetry of the prism array camera and each camera having an optical axis positioned at a first angle relative to the vertical axis of symmetry, the method comprising:

directing light representing the target scene through a plurality of prisms toward the plurality of cameras, each prism of the plurality of prisms corresponding to one of the plurality of cameras and each prism configured to direct a portion of light representing the target scene toward the corresponding camera at least partially by refraction, wherein directing the light comprises, for each prism;

receiving the portion of light through a first surface positioned such that the portion of light representing the target scene enters the prism through the first surface,

reflecting the portion of light from a second surface positioned such that a plane formed by the second surface bisects the first angle between the optical axis of the corresponding camera and the vertical axis of symmetry, and

propagating the reflected light through a third surface positioned such that the light propagating through the third surface exits the prism and travels toward the corresponding camera.

15. The method of claim 14, further comprising, for each camera, receiving the light propagated through the third surface of the corresponding prism at an image sensor of the camera.

16. The method of claim 15, further comprising, via a processor in electronic communication with the plurality of cameras, receiving, from each of the plurality of cameras, an image generated from the light received by the sensor.

17. The method of claim 16, further comprising, via the processor, combining the image from each of the plurality of cameras into a final image of the target scene.

18. The method of claim 14, further comprising, for each camera of the plurality of cameras, reflecting the light propagated through the third surface of the corresponding prism off of an additional light folding surface positioned between the corresponding prism and an image sensor of the camera.

19. The method of claim 18, further comprising, for each camera of the plurality of cameras, refracting the light propagated through the third surface of the corresponding prism through a lens assembly positioned between the third surface and the additional light folding surface.

20. The method of claim 14, wherein in each prism the third surface comprises a negative lens, and wherein propagating the reflected light through a third surface comprises propagating the reflected light through the negative lens.