Camera calibration method and calibration apparatus thereof

Abstract

The invention involves a calibration device for camera calibration, which consists of two vertical grid boards that have distribution grid and the number of signs marked with a unique code point. The invention also provides a method of the camera calibration, including the following steps: (a) Acquisition of images of the calibration device; (2) corresponding coordinates of the signs point to the coordinates of object point; (3) projection the plane grid to get the initial point coordinates of grid point; (4) the use of line extraction intersection to get the precise coordinates of points; (5) The use of 3-D direct linear transformation for the initial value of calibration parameters; (6) iterative solution with beam adjustment to get the camera's internal and external orientation elements. After shooting a picture of calibration device in the invention, the follow-up calibration process can be done automatically by computer. The advantage of the invention is automatic and quickness.

Description

technical field [0001] The invention belongs to the technical field of camera calibration, and in particular relates to a camera calibration method and a used calibration device. Background technique [0002] The process of finding the internal parameters of the camera is called calibration. To restore the 3D shape using the centrally projected image, camera calibration is generally a necessary step. There are several methods for camera calibration. There is a calibration method based on the plane calibration field (Z. Zhang: Flexible Camera Calibration by Viewing a Plane from Unknown Orientations.Proc of 7 th Int.Conference on Computer Vision, Kerkyra, Greece.pp.666-673, Sept.1999.), this method needs to take at least two images of different angles, so it needs to move the plane calibration field or camera, which is difficult to realize automation; The calibration based on the three-dimensional control field is difficult to maintain and inconvenient to carry; there is al...

AI Technical Summary

Problems solved by technology

There is a calibration method based on a plane calibration field (Z. Zhang: Flexible Camera Calibration by Viewing a Plane from Unknown Orientations.Proc of 7 th Int.Conference on Computer Vision, Kerkyra, Greece.pp.666-673, Sept.1999.), this method needs to take at least two images of different angles, so it needs to move the plane calibration field or camera, which is difficult to realize automation; Calibration based on the three-dimensional control field, the three-dimensional control field is difficult to maintain, and it is inconvenient to carry; there is also a self-calibration method that does not require any calibration field, the calculation of the self-calibration method is unstable, and it is not used in many practical applications

In addition, in order to realize the correspondence between image point coordinates and object space point coordinates in the above method, it is generally necessary to manually specify the correspondence of several points

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