Method for calibrating camera based on non-coplanar characteristic point

Abstract

The invention discloses a method for calibrating a camera based on a non-coplanar characteristic point. The method comprises the following steps of: setting a three-dimensional target and establishing a three-dimensional target coordinate system, wherein the three-dimensional target can provide at least six non-coplanar characteristic points; shooting a three-dimensional target image by using a camera, wherein the shot image at least contains six non-coplanar characteristic points; extracting coordinates of the at least six non-coplanar characteristic points in the image coordinate system andsolving a homography between the three-dimensional target coordinate system and the image coordinate system; solving an internal parameter and an external parameter of a camera according to the obtained homography; and carrying out non-linear optimization on the obtained internal parameter and the external parameter. The calibrating method provided by the invention has simple target setting, calibration completion just by shooting the image, flexible use method and higher calibrating precision.

Description

technical field [0001] The invention relates to camera calibration technology, in particular to a camera calibration method based on non-coplanar feature points. Background technique [0002] In recent years, the use of digital cameras for two-dimensional and three-dimensional reconstruction and size detection has been more and more used and researched. The camera model reflects the mapping relationship between the image plane and the spatial position, and the camera calibration is to determine the internal parameters and external parameters that reflect the optical and geometric characteristics of the camera. Among them, the internal parameters of the camera are fixed parameters and do not change with the change of the camera position; the external parameters of the camera reflect the pose relationship between the camera coordinate system and the reference object coordinate system, and this parameter will change with the change of the camera pose. [0003] The traditional ...

AI Technical Summary

Problems solved by technology

This method has certain applicability for cameras with a large field of view, but it is not suitable for cameras with a small field of view that cannot acquire images of multiple planar targets.

Further considering that the ZHANG Z Y. calibration method cannot calibrate the correct camera parameters when the plane target is close to parallel to the camera imaging plane, Zhang Guangjun’s method needs to pay attention to this problem when placing the flexible target position

The calibration method invented by Zhang Guangjun needs to move the camera relative to the flexible target at least once. In some cases, the camera cannot be moved, and it is difficult to ensure that the relative relationship of each sub-target remains unchanged when moving the flexible three-dimensional target.

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