A Camera Calibration Method Based on One-Dimensional Characteristic of Sphere

Abstract

The invention discloses a camera calibration method based on a one-dimensional feature of balls. According to the camera calibration method based on the one-dimensional feature of the balls, the centers of the two balls in different spatial positions and the middle point of a ball center connecting line serve as a one-dimensional calibration object, a plurality of images of one ball at any spatial position are shot, the edge point coordinates of the projection of each ball in the images are extracted, a ball projection quadratic curve is fitted and solved, and the projections of the balls are drawn on the same image; then the projection of the center of each ball is calculated; finally projections of a plurality of sets of ball centers and the projections of the middle points of the ball center connecting lines are obtained, the length ratio of the ball center connecting lines is calculated, and the spatial depth of the center of each ball and camera parameters are further calculated. The camera calibration method based on the one-dimensional feature of balls does not need a traditionally manufactured rod-shaped 1D calibration object, adopts the balls to replace the one-dimensional calibration object, and is suitable for calibration of a multi-camera system due to the fact that the balls are suitable for being observed from any direction. Besides, by means of the camera calibration method, the colinearity of marked points is guaranteed, automatic extraction of the outline of the calibration object is easy, and improvement of accuracy of the projection positions of the centers of the balls is achieved.

Description

technical field [0001] The invention belongs to the field of photogrammetry and computer vision, in particular to a camera calibration method based on the one-dimensional characteristic of a sphere. Background technique [0002] Camera calibration has always been an important issue in photogrammetry and computer vision. At present, there are many camera calibration methods. The early camera calibration methods used three-dimensional calibration objects. Due to the difficulty in making three-dimensional calibration objects, they have been gradually replaced by plane calibration objects. Instead, however, with the emergence and development of multi-camera systems, due to the different viewing angles of multiple cameras, the planar calibration object cannot make multiple cameras with different viewing angles visible at the same time. [0003] Multi-camera calibration often uses a calibration method based on 1-dimensional calibration objects (ZhangZ.Y..Cameracalibrationwithone-d...

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Problems solved by technology

[0006] The purpose of the embodiments of the present invention is to provide a camera calibration method based on the one-dimensional characteristics of a sphere, which aims to solve the problems of complex calibration, inconvenient use, and influence on the calibration results in the existing calibration methods

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