Directional calibration target for camera inner and outer parameter calibration

Abstract

The invention discloses a directional calibration target for camera inner and outer parameter calibration. The directional calibration target is characterized by comprising a checkerboard and directional mark patterns, wherein the checkerboard is formed by black squares and white squares in alternate distribution; the directional mark patterns are arranged in a position near the center position of the checkerboard; the directional mark patterns are three mark circular rings or three mark circles; intersection points of any two diagonally connected black squares or intersection points of any two diagonally connected white squares are used as feature corner points of the directional calibration target; the feature corner points are used for camera calibration; and the directional mark patterns are used for judging the rotation direction of the directional calibration target. The directional calibration target has the advantages that in the camera calibration process, a computer can automatically judge the rotation direction of the directional calibration target; the intelligence and the flexibility of the camera calibration are improved; and the calibration complexity is reduced.

Description

technical field [0001] The invention relates to the field of camera calibration in computer vision, and can be used for calibration of a monocular camera, calibration of a binocular stereo vision system, etc., and specifically relates to a directional calibration target used for calibration of internal and external parameters of a camera. Background technique [0002] Computer vision technology is widely used in industrial control, metrology and other fields. The fundamental problem of computer vision technology is camera calibration. Camera calibration technology is the research focus of computer vision measurement technology. The task of camera calibration is to solve the internal and external parameters of the camera. Calibration technology has received more and more attention and development. [0003] Usually, different camera calibration methods require different types of calibration targets. For example, in 1986, Roger Tsai proposed a camera calibration algorithm based...

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Problems solved by technology

[0003] Usually, different camera calibration methods require different types of calibration targets. For example, in 1986, Roger Tsai proposed a camera calibration algorithm based on radial constraints. This calibration algorithm requires the use of 3D stereo calibration targets, and 3D stereo calibration target volume Therefore, the 3D stereo calibration target makes the calibration process inflexible; around 1999, Zhang Zhengyou (Z.Y Zhang) of Microsoft Research proposed a camera calibration algorithm based on a planar target. Plane target, although the planar target without direction information makes the calibration process flexible, but the rotation direction of the planar target without direction information cannot be judged during the calibration process, but in practical applications, it is often necessary to judge the direction of rotation of the planar target, for example, to carry out When the binocular camera is calibrated, the binocular camera system needs to shoot the same plane target in the space at the same time. At this time, it is necessary to judge the rotation direction of the plane target, thereby establishing a target coordinate system with a fixed position relative to the plane target. The left and right cameras in the camera system have a common target coordinate system, and the spatial position relationship between the left and right cameras can be calculated by using the target coordinate system as a transformation medium

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