Method for linearly solving intrinsic parameters of camera by aid of two concentric circles

Abstract

The invention relates to a method for calibrating a camera by means of solving images of two vanishing points in orthogonal directions or images of circular points by the aid of two concentric circles on a plane and two points which are positioned on one of the circles but are not positioned on the same diameter. The method includes that three images for a target are taken from different directions, and coordinates of a curve and coordinates of two points on each image are extracted; points, which correspond to an image of a circle center and images of two points relative to the circle center, on each curve are computed, and the two vanishing points in the orthogonal directions are acquired from intersection points of straight lines; and a vanishing line on each image can be acquired by implementing a theory of dual quadratic curves of the circular points, the images of the circular points are intersection points of images of the vanishing lines and the circles, constraint equations of the images of the vanishing points in the orthogonal directions or the images of the circular points relative to intrinsic parameters of the camera are established, and the five intrinsic parameters of the camera can be linearly solved. The method has the advantages that full-automatic calibration can be realized owing to the target, errors caused by measurement in a calibration procedure are reduced; and the quadratic curves are concise and comprehensive elements, and accordingly the precision is improved in the calibration procedure.

Description

technical field [0001] The invention belongs to the field of computer research and relates to two concentric circle targets used for solving camera internal parameters. Using any two concentric circles in the scene, the internal parameters of the camera are determined linearly by solving the image coordinates of the ring points on the three images or the coordinates of the vanishing points in two orthogonal directions. Background technique [0002] One of the basic tasks of computer vision is to restore the geometric information of objects in three-dimensional space from the two-dimensional image information obtained by the camera, so as to recognize and reconstruct the geometric shape of objects in three-dimensional space. In this process, the relationship between the three-dimensional geometric position of the spatial object point and its corresponding point in the image must be determined, and this relationship is determined by the geometric model of the camera imaging, a...

AI Technical Summary

Problems solved by technology

[0003] Although the traditional camera calibration method can obtain high precision, it is difficult to make the calibration block and it is not easy to operate

Aiming at this problem, the document "A flexible new technique for camera calibration", (Zhengyou Zhang, IEEE Transactions on Pattern Analysis and Machine Intelligence, vol.22, no.11, pp.1330-1334, 2000.) proposes a planar template Instead of the traditional calibration block method, this method is simple, convenient, low cost, and can obtain high accuracy, but it needs to accurately locate the physical coordinates of the dot matrix on the template

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