Information processing method and apparatus, and recording medium

• US 7,196,721 B2
• Filed: 02/04/2003
• Issued: 03/27/2007
• Est. Priority Date: 02/14/2002
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Uchiyama, Shinji
• Primary Examiner(s): Vu; Ngoc-Yen
• Assistant Examiner(s): DURNFORD GESZVAIN, DILLON
• Application Number:
  US10/357,340
• Publication Number:
  US 20030151665A1
• Time in Patent Office: 1,512 Days
• Field of Search: 348/187, 348/188
• US Class Current: 348/187
• 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

Abstract

A method of setting an internal parameter or an external parameter of a camera is provided. In this method, there is acquired a picked-up image obtained by picking up a calibration pattern in which black pattern elements and black-and-white pattern elements are arranged on a plane using the camera. Then, a black continuation area and a white continuation area are obtained by quantizing the picked-up image, the black pattern elements and the black-and-white pattern elements in the picked-up image are judged from each other based on the obtained black area and white area, the pattern elements in the picked-up image are associated with the pattern elements in a space based on an arrangement relationship between the judged black pattern elements and black-and-white pattern elements, and the internal parameter or the external parameter is set.

Claims

1. An information processing method of setting one of an internal parameter and an external parameter of a camera, comprising:

acquiring a picked-up image obtained by picking up a calibration pattern in which black pattern elements and black-and-white pattern elements are arranged on a plane using the camera, each of the black pattern elements having a dark closed area in a bright background area, each of the black-and-white pattern elements having a dark closed area and a bright closed area inside the dark closed area;

obtaining a black continuation area and a white continuation area by quantizing the picked-up image;

judging the black pattern elements and the black-and-white pattern elements in the picked-up image based on the black continuation area and the white continuation area which are obtained in said obtaining step; and

identifying which of the black-and-white pattern elements, in the calibration pattern, correspond to each of the judged black-and-white pattern elements, based on an arrangement relation of the judged black-and-white pattern elements;

identifying which of the black pattern elements, in the calibration pattern, correspond to each of the judged black pattern elements, based on the arrangement relation of the judged black-and-white pattern elements; and

setting at least one of the internal parameter and the external parameter based on correspondence between image coordinate values of the pattern elements on the picked-up image and spatial coordinate values of the pattern elements in a space, the correspondence being obtained by the identifying of the black-and-white pattern elements and the identifying of the black pattern elements,

wherein the calibration pattern includes three or more black-and-white pattern elements arranged on a line and a black-and-white pattern element arranged at a position perpendicular to the line.

2. An information processing method according to claim 1,

wherein each of the black pattern elements is a black circle area, and

each of the black-and-white pattern elements is a black circle area and is a pattern element having a concentric white circle area inside the black circle area.

3. An information processing method according to claim 1,

wherein if center-of-gravity points of the black continuation area and the white continuation area are almost the same, these areas are judged as the black-and-white pattern element.

6. A program stored on a computer-readable storage medium for realizing the information processing method according to claim 1.

7. A computer-readable storage medium that stored a program for realizing the information processing method according to claim 1.

4. An information processing method of setting one of an internal parameter and an external parameter of a camera, comprising:

acquiring a picked-up image obtained by picking up a calibration pattern in which white pattern elements and white-and-black pattern elements are arranged on a plane using the camera, each of the white pattern elements having a bright closed area in a dark background area, each of the white-and-black pattern elements having a bright closed area and a dark closed area inside the bright closed area;

obtaining a white continuation area and a black continuation area by binarizing the picked-up image;

judging between the white pattern elements and the white-and-black pattern elements in the picked-up image based on the white continuation area and the black continuation area which are obtained;

identifying which of the white-and-black pattern elements, in the calibration pattern, correspond to each of the judged white-and-black pattern elements, based on an arrangement relation of the judged white-and-black pattern elements;

identifying which of the white pattern elements, in the calibration pattern, correspond to each of the judged white pattern elements based on the arrangement relation of the judged white-and-black pattern elements; and

setting at least one of the internal parameter and the external parameter of the camera based on correspondence between image coordinate values of the pattern elements on the picked-up image and spatial coordinate values of the pattern elements in a space, the correspondence being obtained by the identifying of the white-and-black pattern elements and the identifying of the white pattern elements,

wherein the calibration pattern includes three or more white-and-black pattern elements arranged on a line and a white pattern element arranged at a position perpendicular to the line.

5. An information processing method of setting one of an internal parameter and an external parameter of a camera, comprising:

acquiring a picked-up image obtained by picking up a calibration pattern in which first pattern elements and second pattern elements are arranged using the camera, each of the first pattern elements being expressed by two closed areas having different brightness, each of the second pattern elements being expressed by one closed area;

quantizing a signal expressing brightness in the picked-up image and detecting the first pattern elements and the second pattern elements based on a result of the quantization;

identifying which of the first pattern elements, in the calibration pattern, correspond to each of the judged first pattern elements based on an arrangement relation of the judged first pattern elements;

identifying which of the second pattern elements, in the calibration pattern, correspond to each of the judged second pattern elements based on the arrangement relation of the judged first pattern elements; and

setting at least one of the internal parameter and the external parameter of the camera based on correspondence between image coordinate values of the pattern elements on the picked-up image and spatial coordinate values of the pattern elements in a space, the correspondence being obtained by the identifying of the first pattern elements and the identifying of the second pattern elements,

wherein the calibration pattern includes three or more first pattern elements arranged on a line and a first pattern element arranged at a position perpendicular to the line.

8. An information processing apparatus that sets one of an internal parameter and an external parameter of a camera, comprising:

a calibration pattern in which black pattern elements and black-and-white pattern elements are arranged on a plane using the camera, each of the black pattern elements being expressed by a dark closed area in a bright background area, each of the black-and-white pattern elements being expressed by a dark closed area and a bright closed area inside the dark closed area;

an acquisition unit that acquires a picked-up image obtained by picking up the calibration pattern using the camera;

a detecting unit that quantizes a signal expressing brightness in the picked-up image and detects the black pattern elements and the black-and-white pattern elements based on a result of the quantization and that obtains a black continuation area and a white continuation area as a result of the quantization;

a judging unit that judges the black pattern elements and the black-and-white pattern elements in the picked-up image based on the black continuation area and the white continuation area;

a unit that identifies which of the black-and-white pattern elements, in the calibration pattern, correspond to each of the judged black-and-white pattern elements, based on an arrangement relation of the judged black-and-white pattern elements;

a unit that identifies which of the black pattern elements, in the calibration pattern, correspond to each of the judged black pattern elements, based on the arrangement relation of the judged black-and-white pattern elements; and

a setting unit that sets at least one of the internal parameter and the external parameter of the camera based on correspondence between image coordinate values of the pattern elements on the picked-up image and spatial coordinate values of the pattern elements in a space, the correspondence being obtained by the identifying of the black-and-white pattern elements and the identifying of the black pattern elements,

wherein the calibration pattern includes three or more black-and-white pattern elements arranged on a line and a black-and-white pattern element arranged at a position perpendicular to the line.