Method and apparatus for calibrating multiple cameras using mirrors

Patent metadata

Field	Value
Publication number	US-9948926-B2
Application number	US-201615073894-A
Country	US
Kind code	B2
Filing date	Mar 18, 2016
Priority date	May 8, 2015
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

Method and apparatus for calibrating multiple cameras. A first mirror and a second mirror are arranged opposite each other. An object is disposed between the first mirror and the second mirror. Calibration of the multiple cameras is performed using a figure of the object formed on the second mirror via reflection from the first mirror and the second mirror.

First claim

What is claimed is:

1. An apparatus for calibrating multiple cameras, comprising:
a first mirror;
a second mirror arranged opposite the first mirror; and
an object disposed between the first mirror and the second mirror,
wherein multiple cameras are calibrated using a figure of the object formed on the second mirror via reflection from the first mirror and the second mirror,
wherein the object has a first shape viewed in a direction of the first mirror and a second shape, which is different from the first shape, viewed in a direction of the second mirror, and
when a figure of the first shape and a figure of the second shape are repeatedly indicated in an image acquired when the multiple cameras capture the image of the second mirror, calibration of the multiple cameras is applied using the figure of the first shape and the figure of the second shape.

2. The apparatus of claim 1 , wherein each of the first mirror and the second mirror is a reflection mirror.

3. The apparatus of claim 1 , wherein the first mirror and the second mirror are arranged parallel to each other.

4. The apparatus of claim 1 , wherein the first mirror has flatness equal to or greater than a predefined first threshold, and the second mirror has flatness equal to or greater than a predefined second threshold.

5. The apparatus of claim 1 , wherein the object includes a combination of a plurality of points having a relative geometric relationship therebetween.

6. The apparatus of claim 1 , wherein the object has a plurality of faces,
at least some of the plurality of faces have different colors or contours from each other.

7. The apparatus of claim 1 , wherein the object has a plurality of faces, and
at least some of the plurality of faces have different numbers or symbols from each other.

8. The apparatus of claim 1 , wherein the object has a plurality of faces, and
a part of the plurality of faces corresponds to a front face viewed in a direction of the first mirror, and a remaining part of the plurality of faces corresponds to a rear face viewed in a direction of the second mirror.

9. The apparatus of claim 8 , wherein the object is configured such that a pattern of points indicated on the front face is identical to a pattern of points indicated on the rear face, and a character indicated on the front face is different from a character indicated on the rear face.

10. The apparatus of claim 8 , wherein each of the front face and the rear face includes five or more surfaces.

11. The apparatus of claim 1 , wherein:
at least one of the first shape or second shape has a pattern or a character that is viewed in the direction of only one mirror between the first and second mirror.

12. The apparatus of claim 1 , wherein shapes in the image are classified into the first shape and the second shape, thus enabling overlapping figures in the image to be distinguished from each other.

13. The apparatus of claim 1 , wherein the multiple cameras are arranged towards the second mirror.

14. The apparatus of claim 1 , wherein a distance between the multiple cameras and the object, suitable for a purpose of use of the multiple cameras, is simulated using a distance between the first mirror and the second mirror and a distance between the second mirror, the object, and the multiple cameras.

15. The apparatus of claim 1 , wherein calibration of the multiple cameras is performed using a region of interest in an image captured by the multiple cameras.

16. The apparatus of claim 15 , wherein the region of interest is a region, brightness of which is equal to or greater than a predefined level, in the captured image.

17. The apparatus of claim 15 , further comprising a light source for adjusting a size of the region of interest by adjusting an amount of emitted light.

18. The apparatus of claim 1 , further comprising:
a first mirror motion stage configured to adjust a position of the first mirror;
a second mirror motion stage configured to adjust a position of the second mirror;
an object motion stage configured to adjust a position of the object; and
a multiple-camera motion stage configured to adjust a position of the multiple cameras.

19. A method for calibrating multiple cameras, comprising:
setting up an environment for calibration of multiple cameras;
capturing an image of a second mirror using the multiple cameras, thus generating the image;
acquiring information for calibration of the multiple cameras using the image; and
performing calibration of the multiple cameras using the acquired information,
wherein a first mirror and the second mirror are arranged opposite each other, and
wherein the image indicates a figure of an object formed on the second mirror via reflection from the first mirror and the second mirror,
wherein the object has a first shape viewed in a direction of the first mirror and a second shape, which is different from the first shape, viewed in a direction of the second mirror, and
when a figure of the first shape and a figure of the second shape are repeatedly indicated in an image acquired when the multiple cameras capture the image of the second mirror, calibrating the multiple cameras using the figure of the first shape and the figure of the second shape.

20. A method for calibrating multiple cameras, the method being performed by multiple cameras disposed between a first mirror and a second mirror, the method comprising:
capturing an image of the second mirror, thus generating the image;
acquiring information for calibration using the image; and
performing calibration using the acquired information,
wherein the first mirror and the second mirror are arranged opposite each other, and
wherein the image indicates a figure of an object formed on the second mirror via reflection from the first mirror and the second mirror,
wherein the object has a first shape viewed in a direction of the first mirror and a second shape, which is different from the first shape, viewed in a direction of the second mirror, and
when a figure of the first shape and a figure of the second shape are repeatedly indicated in an image acquired when the multiple cameras capture the image of the second mirror, calibrating the multiple cameras using the figure of the first shape and the figure of the second shape.

Assignees

• Electronics & Telecommunications Res Inst

Inventors

• Kang Hyun
• Kim Jae-Hean
• Park Chang-Joon
• Choi Jin-Sung

Classifications

• H04N17/002 Primary

  for television cameras · CPC title

• G03B43/02

  Testing shutters · CPC title

• G03B43/00

  Testing correct operation of photographic apparatus or parts thereof · CPC title

• H04N23/90

  Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums · CPC title

• G02B17/004

  Systems comprising a plurality of reflections between two or more surfaces, e.g. cells, resonators (multipass arrangements for optical cuvettes G01N21/031; laser resonators H01S3/05) · CPC title