Capturing and processing of high dynamic range images using camera arrays

• US 9,041,829 B2
• Filed: 09/02/2014
• Issued: 05/26/2015
• Est. Priority Date: 05/20/2008
• Status: Active Grant

• Current Assignee: FotoNation Limited (Adeia Inc.)
• Original Assignee: Pelican Imaging Corporation
• Inventors: Venkataraman, Kartik, Jabbi, Amandeep S., Mullis, Robert H.
• Primary Examiner(s): LAM, HUNG H
• Application Number:
  US14/475,477
• Publication Number:
  US 20140368685A1
• Time in Patent Office: 266 Days
• Field of Search: 348/208.1, 348/218.1, 348/229.1, 348/234, 348/290, 348/335, 348/340, 348/362
• US Class Current: 348/222.1
• CPC Class Codes: G02B 13/0015 characterised by the lens design
• CPC Class Codes: G02B 13/0085 employing wafer level optics
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G02B 27/1066 for enhancing image performance, like resolution, pixel numbers, dual magnifications or dynamic range, by tiling, slicing or overlapping fields of view
• CPC Class Codes: G02B 27/123 The splitting element being a lens or a system of lenses, including arrays and surfaces with refractive power
• CPC Class Codes: G02B 3/0006 Arrays G02B3/02, G02B5/188 take precedence
• CPC Class Codes: G02B 5/20 Filters polarising elements G02B5/30
• CPC Class Codes: G02B 5/208 for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation
• CPC Class Codes: G06T 1/20 Processor architectures; Processor configuration, e.g. pipelining
• CPC Class Codes: G06T 2207/10052 Images from lightfield camera
• CPC Class Codes: G06T 2207/30244 Camera pose
• CPC Class Codes: G06T 3/4053 based on super-resolution, i.e. the output image resolution being higher than the sensor resolution
• CPC Class Codes: G06T 7/50 Depth or shape recovery
• CPC Class Codes: G06T 7/55 from multiple images
• CPC Class Codes: G06T 7/557 from light fields, e.g. from plenoptic cameras
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14632 Wafer-level processed structures
• CPC Class Codes: H01L 27/14685 : Process for coatings or optical elements
• CPC Class Codes: H01L 27/14687 : Wafer level processing
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H04N 1/195 : the array comprising a two-dimensional array or a combination of two-dimensional arrays
• CPC Class Codes: H04N 1/19589 : Optical means, e.g. an optical fibre bundle, for mapping the whole or a part of a scanned image onto the array
• CPC Class Codes: H04N 1/19594 : using a television camera or a still video camera
• CPC Class Codes: H04N 13/128 : Adjusting depth or disparity
• CPC Class Codes: H04N 13/243 : using three or more 2D image sensors
• CPC Class Codes: H04N 13/257 : Colour aspects
• CPC Class Codes: H04N 2013/0081 : Depth or disparity estimation from stereoscopic image signals
• CPC Class Codes: H04N 23/10 : for generating image signals from different wavelengths
• CPC Class Codes: H04N 23/40 : Circuit details for pick-up tubes
• 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 23/54 : Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
• CPC Class Codes: H04N 23/60 : Control of cameras or camera modules
• CPC Class Codes: H04N 23/69 : Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
• 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 23/90 : Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums
• CPC Class Codes: H04N 23/951 : by using two or more images to influence resolution, frame rate or aspect ratio
• CPC Class Codes: H04N 25/00 : Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 25/131 : including elements passing infrared wavelengths
• CPC Class Codes: H04N 25/134 : based on three different wavelength filter elements
• CPC Class Codes: H04N 25/135 : based on four or more different wavelength filter elements
• 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: H04N 25/534 : depending on the spectral component
• CPC Class Codes: H04N 25/581 : acquired simultaneously
• CPC Class Codes: H04N 25/60 : Noise processing, e.g. detecting, correcting, reducing or removing noise
• CPC Class Codes: H04N 25/616 : involving a correlated sampling function, e.g. correlated double sampling [CDS] or triple sampling
• CPC Class Codes: H04N 25/74 : Circuitry for scanning or addressing the pixel array
• CPC Class Codes: H04N 5/262 : Studio circuits, e.g. for mixing, switching-over, change of character of image, other special effects ; Cameras specially adapted for the electronic generation of special effects
• 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
• CPC Class Codes: H04N 5/265 : Mixing
• CPC Class Codes: H04N 5/33 : Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

A camera array, an imaging device and/or a method for capturing image that employ a plurality of imagers fabricated on a substrate is provided. Each imager includes a plurality of pixels. The plurality of imagers include a first imager having a first imaging characteristics and a second imager having a second imaging characteristics. The images generated by the plurality of imagers are processed to obtain an enhanced image compared to images captured by the imagers. Each imager may be associated with an optical element fabricated using a wafer level optics (WLO) technology.

Claims

1. A camera array, comprising:

a plurality of cameras configured to capture images of a scene from different viewpoints, where each camera comprises;

optics comprising at least one lens element and at least one aperture; and

a sensor comprising a two dimensional array of pixels and control circuitry for controlling imaging parameters; and

at least one spectral filter located within the camera, where each spectral filter is configured to pass a specific spectral band of light;

a controller configured to control operation parameters of the plurality of cameras; and

an image processing pipeline module;

wherein the controller configures the plurality of cameras so that cameras having the same filter type operate at different exposures simultaneously; and

wherein the image processing pipeline module is configured to process images captured by the plurality of cameras to generate a high dynamic range image by;

linearizing the camera response in images captured by cameras having the same filter type and different exposures based upon the exposure of the camera that captured the image;

measuring parallax using images captured by the plurality of cameras;

registering images captured by the plurality of cameras to account for the difference in the viewpoints of the cameras using measured parallax; and

combining linearized images registered to account for differences in the viewpoints of the plurality of cameras using measured parallax to obtain a high dynamic range image.

2. The camera array of claim 1, wherein each camera includes a filter selected from the group consisting of a Bayer filter, one or more Blue filters, one or more Green filters, one or more Red filters, one or more shifted spectral filters, one or more near-IR filters, and one or more hyper-spectral filters.

3. The camera array of claim 1, wherein the plurality of cameras comprises a central camera and forms:

at least one row of cameras above the central camera;

at least one row of cameras below the central camera;

at least one column of cameras to the left of the central camera; and

at least one column of cameras to the right of the central camera;

wherein cameras having the same filter type and exposure are located in locations selected from the group consisting of;

locations including at least one row in the camera array above the central camera and at least one row in the camera array below the central camera; and

locations including at least one column in the camera array to the left of the central camera and at least one column in the camera array to the right of the central camera.

4. The camera array of claim 3, wherein the camera array comprises a 3×

3 array of cameras.

5. The camera array of claim 3, wherein the camera array comprises a 4×

4 array of cameras.

6. The camera array of claim 3, wherein the camera array comprises a 5×

5 array of cameras.

7. The camera array of claim 1, wherein the plurality of cameras forms a linear array of cameras.

8. The camera array of claim 7, wherein the linear array of cameras comprises at least one selected from the group consisting of:

a 1×

4 array of cameras; and

a 1×

10 array of cameras.

9. The camera array of claim 1, wherein the control circuitry of the different types of cameras configures the cameras that operate at different exposures to operate with at least one difference in operating parameters.

10. The camera array of claim 9, wherein the at least one difference in operating parameters includes at least one imaging parameter selected from the group consisting of exposure, and gain.

11. The camera array of claim 1, wherein the plurality of cameras comprises a distribution of cameras selected from the group consisting of:

a symmetric distribution of cameras of different types; and

an irregular distribution of cameras of different types.

12. The camera array of claim 1, wherein the camera array is a monolithic camera array assembly comprising:

a lens element array forming the optics of each camera; and

a single semiconductor substrate on which all of the pixels and control circuitry for each camera are formed.

13. The camera array of claim 1, wherein the plurality of cameras are formed on separate semiconductor substrates.

14. The camera array of claim 1, wherein

images captured by the plurality of cameras include different occlusions sets, where the occlusion set of a first camera is the portion of a scene visible to a second camera in the plurality of cameras that is occluded from the view of the first camera;

and

wherein the image processing pipeline module comprises a parallax confirmation and measurement module configured to measure parallax using images captured by the plurality of cameras by;

detecting parallax-induced changes that are consistent across the captured images taking into account the position of the cameras that captured the images and the different exposures; and

ignoring pixels in the images captured by the plurality of cameras that are in the occlusion set of the central camera.

15. The camera array of claim 14, wherein the parallax confirmation and measurement module is further configured to estimate distance to an object in images captured by the plurality of cameras.

16. The camera array of claim 14, wherein the parallax confirmation and measurement module is further configured to generate a depth map using images captured by the plurality of cameras.

17. The camera array of claim 14, wherein the image processing pipeline module further comprises a super-resolution processing module configured to generate at least one higher resolution image using images captured by the plurality of cameras and parallax measurements from the parallax confirmation and measurement module to compensate for parallax in the captured images.

18. The camera array of claim 17, wherein the parallax information includes a depth map.

19. A camera array, comprising:

a monolithic integrated module forming an array of cameras, where the monolithic integrated module comprises;

a lens element array forming the optics of each of the plurality of cameras, where the optics of each camera comprises at least one lens element and at least one aperture; and

a single semiconductor substrate on which all of the pixels and control circuitry for each camera are formed;

a controller configured to control operation parameters of the plurality of cameras; and

an image processing pipeline module;

wherein the controller configures the plurality of cameras so that cameras having the same filter type operate at different exposures simultaneously; and

wherein the image processing pipeline module is configured to process images captured using the cameras to generate a high dynamic range image by;

linearizing the camera response in images captured by cameras having the same filter type and different exposures based upon the exposure of the camera that captured the image;

measuring parallax using images captured by the plurality of cameras;

registering images captured by the plurality of cameras to account for the difference in the viewpoints of the cameras using measured parallax; and

combining linearized images registered to account for differences in the viewpoints of the plurality of cameras using measured parallax to obtain a high dynamic range image;

wherein images captured by the plurality of cameras include different occlusions sets, where the occlusion set of a first camera is the portion of a scene visible to a second camera in the plurality of cameras that is occluded from the view of the first camera; and

wherein the image processing pipeline module comprises a parallax confirmation and measurement module configured to measure parallax using images captured by the plurality of cameras by;

detecting parallax-induced changes that are consistent across the captured images taking into account the position of the cameras that captured the images and the different exposures; and

ignoring pixels in the images captured by the plurality of cameras that are in the occlusion set of the central camera.

20. A camera array, comprising:

a plurality of cameras formed on separate semiconductor substrates and mounted to a motherboard, where each camera comprises;

optics comprising at least one lens element and at least one aperture; and

a sensor comprising a two dimensional array of pixels and control circuitry for controlling imaging parameters;

a controller configured to control operation parameters of the plurality of cameras; and

an image processing pipeline module;

wherein the controller configures the plurality of cameras so that cameras having the same filter type operate at different exposures simultaneously; and

wherein the image processing pipeline module is configured to process images captured using the plurality of cameras to generate a high dynamic range image by;

linearizing the camera response in images captured by cameras having the same filter type and different exposures based upon the exposure of the camera that captured the image;

measuring parallax using images captured by the plurality of cameras; and

registering images captured by the plurality of cameras to account for the difference in the viewpoints of the cameras using measured parallax; and

combining linearized images registered to account for differences in the viewpoints of the plurality of cameras using measured parallax to obtain a high dynamic range image;

wherein images captured by the plurality of cameras include different occlusions sets, where the occlusion set of a first camera is the portion of a scene visible to a second camera in the plurality of cameras that is occluded from the view of the first camera; and

wherein the image processing pipeline module comprises a parallax confirmation and measurement module configured to measure parallax using images captured by the plurality of cameras by;

detecting parallax-induced changes that are consistent across the captured images taking into account the position of the cameras that captured the images and the exposures; and

ignoring pixels in the images captured by the plurality of cameras that are in the occlusion set of the central camera.

21. The camera array of claim 20, wherein the super-resolution processing module is configured to select at least one distance as a focal plane and to apply blurring to pixels in at least one higher resolution image with depths in the depth map that are not proximate a focal plane.