Calibration plate for calibrating a plurality of image capturing devices and method for calibrating a plurality of image capturing devices

Patent metadata

Field	Value
Publication number	US-9749621-B2
Application number	US-201314095062-A
Country	US
Kind code	B2
Filing date	Dec 3, 2013
Priority date	Dec 27, 2012
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

A calibration plate and a method for calibrating image capturing devices are provided. The calibration plate includes: a plate having a front face and a rear face; a plurality of calibration patterns formed at the front face of the plate, arranged in a regular manner, and used to calibrate image distortions, lens aberrations, and image center positions for the image capturing devices; and a plurality of graphically encoded patterns formed at the front face of the plate, the graphically encoded patterns being different from each other, and the graphically encoded patterns having information providing the positions of the calibration patterns.

First claim

What is claimed is:

1. A calibration plate for calibrating a plurality of image capturing devices, comprising:
a plate, having a front face and a rear face;
a plurality of calibration patterns, formed at the front face of the plate, and arranged in a regular manner, wherein the calibration patterns are used to calibrate image distortions, lens aberrations, and image center position for the image capturing devices; and
a plurality of graphically encoded patterns, formed at the front face of the plate, and being different from each other, wherein the graphically encoded patterns are located dispersedly between the adjacent calibration patterns,
wherein the calibration patterns are also formed at the rear face of the plate, the graphically encoded patterns are also formed at the rear face of the plate, and the calibration patterns and the graphically encoded patterns formed at the rear face of the plate have a relative or consistent relationship with the calibration patterns and the graphically encoded patterns formed at the front face of the plate.

2. The calibration plate according to claim 1 , wherein each graphically encoded pattern is adjacent to any of the calibration patterns.

3. The calibration plate according to claim 2 , wherein the graphically encoded patterns record positions and orientations of the calibration patterns adjacent to the graphically encoded patterns.

4. The calibration plate according to claim 1 , wherein the graphically encoded patterns are recognizable graphs: one-dimensional barcodes, two-dimensional barcodes, digitals, text, and symbols or a combination thereof.

5. The calibration plate according to claim 1 , wherein the graphically encoded patterns comprise a first encoded pattern, a second encoded pattern, and a third encoded pattern, the first encoded pattern represents a quadrant position, the second encoded pattern represents a horizontal axis position, and the third encoded pattern represents a vertical axis position.

6. The calibration plate according to claim 5 , wherein the graphically encoded patterns further comprise a fourth encoded pattern, the fourth encoded pattern representing an extension state, and the extension state refers to that when graphs of the second encoded pattern or third encoded pattern are insufficient for use to denote positions and orientations of the calibration patterns on the calibration plate, the fourth encoded pattern is used to perform position grouping.

7. A method for calibrating a plurality of image capturing devices, comprising the following steps of:
placing a calibration plate on a platform, wherein the calibration plate is located at observation positions of the image capturing devices, wherein the calibration plate comprises:
a plate, having a front face and a rear face;
a plurality of calibration patterns, formed at the front face of the plate, and arranged in a regular manner, wherein the calibration patterns are used to calibrate image distortions, lens aberrations, and image center position for the image capturing devices; and
a plurality of graphically encoded patterns, formed at the front face of the plate, and being different from each other, wherein the graphically encoded patterns are located dispersedly between the adjacent calibration patterns;
photographing a plurality of graphically encoded patterns on the calibration plate by the image capturing devices, so as to obtain a first group of coordinate data; and
determining relative positions of the image capturing devices based on the first group of coordinate data, so as to calibrate information about relative positions and orientations of the image capturing devices.

8. The calibration method according to claim 7 , further comprising the following steps of:
photographing a plurality of calibration patterns on the calibration plate by each image capturing device, so as to obtain calibration data corresponding to the plurality of the image capturing devices; and
calibrating image distortions, lens aberrations, and image center positions for the image capturing devices based on the calibration data.

9. The calibration method according to claim 7 , wherein each image capturing device photographs nine calibration patterns on the calibration plate.

10. The calibration method according to claim 7 , further comprising the following steps of:
moving the platform;
photographing the graphically encoded patterns on the calibration plate by the image capturing devices, so as to obtain a second group of coordinate data; and
calibrating relevant information of the image capturing devices and the platform based on the first group of coordinate data and the second group of coordinate data.

11. The calibration method according to claim 10 , wherein the relevant information of the image capturing devices and the platform comprises: relative position relationships between the image capturing devices and the platform or a movement state of the platform.

12. A method for calibrating a plurality of image capturing devices, comprising the following steps of:
placing a calibration plate on a first platform, wherein the calibration plate is located at observation positions of a first group of image capturing devices;
photographing a plurality of graphically encoded patterns on the calibration plate by the first group of image capturing devices, so as to obtain a first group of coordinate data;
determining relative positions of the first group of image capturing devices based on the first group of coordinate data, so as to calibrate information about relative positions and orientations of the first group of image capturing devices;
transferring the calibration plate to a second platform, wherein the calibration plate is located at observation positions of a second group of image capturing devices;
photographing a plurality of graphically encoded patterns on the calibration plate by the second group of image capturing devices, so as to obtain a second group of coordinate data; and
calibrating relevant information between the first group and the second group of image capturing devices, and establishing a global coordinate system to connect with the first and second platforms based on the first group of coordinate data and the second group of coordinate data.

13. The calibration method according to claim 12 , wherein the calibration plate is transferred from the first platform to the second platform in a translation or rotation manner.

14. The calibration method according to claim 12 , wherein the graphically encoded patterns on the calibration plate are photographed by the first group of image capturing devices, so as to obtain the first group of coordinate data; and the graphically encoded patterns on the calibration plate are photographed by the second group of image capturing devices, so as to obtain the second group of coordinate data.

Assignees

• Metal Ind Res & Dev Ct

Inventors

• Lin Shi-Wei
• Wen Chih-Chin
• Hung Kuo-Kai
• Huang Chia-Chu
• Chang Hao-Jhen

Classifications

• H04N17/002 Primary

  for television cameras · CPC title