Multi-target camera calibration

• US 9,596,459 B2
• Filed: 09/26/2014
• Issued: 03/14/2017
• Est. Priority Date: 09/05/2014
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Keaffaber, Todd, Middleton, Daniel, Goncalves de Lima, Gilson, Meloun, Martin, Nasery, Varun, Shi, Jianbo, Manchanda, Kabeer, Kim, Philip, Bernard, Christopher, Niu, Yedong
• Primary Examiner(s): Chevalier, Robert
• Application Number:
  US14/498,793
• Publication Number:
  US 20160073101A1
• Time in Patent Office: 900 Days
• Field of Search: 386/200, 386/210, 386/223, 386/227, 386/230, 386/242, 348/61, 348/92, 348/94, 348/95
• US Class Current: 1/1
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30208 Marker matrix
• CPC Class Codes: G06T 7/80 Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
• CPC Class Codes: H04N 17/002 for television cameras
• 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 23/90 Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums

Abstract

Techniques for calibration of image capturing devices are described herein. The techniques include capturing one or more images at a first target, capturing one or more images at a second target, capturing one or more images at a third target, capturing one or more images at a fourth target, and calibrating a multi-camera system based on the captured images.

Claims

1. A system for calibrating a multi-camera system, comprising:

a processing device; and

modules to be implemented by the processing device, the modules comprising;

an image capture module to;

capture one or more images at a first target;

capture one or more images at a second target;

capture one or more images at a third target;

capture one or more images at a fourth target;

a motorized platform to receive a device housing the multi-camera system at a first position associated with the first target;

a rotation module to;

rotate the device about 45 degrees to a second position associated with the second target;

rotate the device about 10 degrees to a third position associated with the second target;

rotate the device about 135 degrees to a fourth position associated with the third target;

rotate the device about 180 degrees to a fifth position associated with the fourth target;

rotate the device about 10 degrees to a sixth position associated with the fourth target; and

calibration module to calibrate a multi-camera system based on the captured images.

2. The system of claim 1, further comprising a storage device, wherein the calibration module is to store calibration data associated with the calibration.

3. The system of claim 1, wherein:

one image is captured at the first target;

two images are captured at the second target;

one image is captured at the third target; and

two images are captured at the fourth target.

4. The system of claim 1, the modules further comprising a debugging module to:

confirm all cameras of the multi-camera system are showing a preview before calibration;

confirm that the first target is positioned within a preview window before image capture is performed;

confirm that all targets are pointing directly the multi-camera system at a predetermined distance from the multi-camera system;

or

any combination thereof.

5. The system of claim 1, wherein:

the first target is a checkerboard pattern rectangle about 410 millimeters (mm) tall and about 620 mm wide;

the second target is a checkerboard pattern rectangle about 620 mm tall and about 900 mm wide;

the third target comprises five checkerboard pattern rectangles comprising;

a first checkerboard pattern rectangle about 60 mm tall and 60 mm wide;

four checkerboard pattern rectangles each attached to an edge of the first checkerboard pattern rectangle, the four checkerboard patterns disposed at an angle of about 40 degrees from each other; and

the fourth target is similar to the third target except that the fourth target is disposed at a distance from the multi-camera system that is farther than the distance at which the third target is disposed.

6. The system of claim 5, further comprising a position determination module to capture an image of each checkerboard pattern of the third target, the fourth target, or any combination thereof.

7. The system of claim 6, wherein the position determination module is to stich individual images captured of each checkerboard pattern together based on a position of each checkerboard pattern relative to other checkerboard patterns in the target.

8. The system of claim 1, wherein a center of each of the targets and the multi-camera system are disposed about 90 centimeters (cm) above the ground.

9. The system of claim 1, wherein:

a distance between the multi-camera system and the first target is about 800 mm;

a distance between the multi-camera system and the second target is about 1200 mm;

a distance between the multi-camera system and the third target is about 2230 mm; and

a distance between the multi-camera system on the fourth target is about 3050 mm.

10. A method for calibrating a multi-camera system, comprising:

capturing one or more images at a first target, wherein the first target is a checkerboard pattern rectangle about 410 millimeters (mm) tall and about 620 mm wide;

capturing one or more images at a second target, wherein the second target is a checkerboard pattern rectangle about 620 mm tall and about 900 mm wide;

capturing one or more images at a third target, wherein the third target comprises five checkerboard pattern rectangles comprising;

a first checkerboard pattern rectangle about 60 mm tall and 60 mm wide;

four checkerboard pattern rectangles each attached to an edge of the first checkerboard pattern rectangle, the four checkerboard patterns disposed at an angle of about 40 degrees from each other;

capturing one or more images at a fourth target, wherein the fourth target is similar to the third target except that the fourth target is disposed at a distance from the multi-camera system that is farther than the distance at which the third target is disposed; and

calibrating a multi-camera system based on the captured images.

11. The method of claim 10, further comprising a storage device, wherein the calibration module is to store calibration data associated with the calibration.

12. The method of claim 10, wherein:

one image is captured at the first target;

two images are captured at the second target;

one image is captured at the third target; and

two images are captured at the fourth target.

13. The method of claim 10, further comprising:

a motorized platform to receive a device housing the multi-camera system at a first position associated with the first target;

a rotation module to;

rotate the device about 45 degrees to a second position associated with the second target;

rotate the device about 10 degrees to a third position associated with the second target;

rotate the device about 135 degrees to a fourth position associated with the third target;

rotate the device about 180 degrees to a fifth position associated with the fourth target;

rotate the device about 10 degrees to a sixth position associated with the fourth target.

14. The method of claim 10, the modules further comprising a debugging module to:

confirm all cameras of the multi-camera system are showing a preview before calibration;

confirm that the first target is positioned within a preview window before image capture is performed;

confirm that all targets are pointing directly the multi-camera system at a predetermined distance from the multi-camera system;

or

any combination thereof.

15. The method of claim 10, further comprising a position determination module to capture an image of each checkerboard pattern of the third target, the fourth target, or any combination thereof.

16. The method of claim 15, wherein the position determination module is to stich individual images captured of each checkerboard pattern together based on a position of each checkerboard pattern relative to other checkerboard patterns in the target.

17. The method of claim 10, wherein a center of each of the targets and the multi-camera system are disposed about 90 centimeters (cm) above the ground.

18. The method of claim 10, wherein:

a distance between the multi-camera system and the first target is about 800 mm;

a distance between the multi-camera system and the second target is about 1200 mm;

a distance between the multi-camera system and the third target is about 2230 mm; and

a distance between the multi-camera system on the fourth target is about 3050 mm.

19. A non-transitory computer readable medium including code, when executed, to cause a processing device to:

capture one or more images at a first target;

capture one or more images at a second target;

capture one or more images at a third target;

capture one or more images at a fourth target; and

calibrate a multi-camera system based on the captured images, wherein the code is to confirm all cameras of the multi-camera system are showing a preview before calibration, confirm that the first target is positioned within a preview window before image capture is performed, confirm that all targets are pointing directly the multi-camera system at a predetermined distance from the multi-camera system, or any combination thereof.

20. The computer readable medium of claim 19, further comprising code to store calibration data associated with the calibration.

21. The computer readable medium of claim 19, wherein:

one image is captured at the first target;

two images are captured at the second target;

one image is captured at the third target; and

two images are captured at the fourth target.

22. The computer readable medium of claim 19, further comprising code to:

rotate the device about 45 degrees from a first position associated with the first target to a second position associated with the second target;

rotate the device about 10 degrees to a third position associated with the second target;

rotate the device about 135 degrees to a fourth position associated with the third target;

rotate the device about 180 degrees to a fifth position associated with the fourth target;

rotate the device about 10 degrees to a sixth position associated with the fourth target.