Calibration method of camera in CT system

Abstract

The invention provides a calibration method of a camera in a CT system. The method comprises the following steps: acquiring an image of a CT sickbed in a moving process through the camera with a fixedposition and a fixed visual angle; establishing a camera coordinate system, selecting one or more angular points of a sickbed as reference points, and detecting coordinates of the reference points from all the acquired images through an angular point detection method; selecting an image of which the reference point is closest to the center of the camera during acquisition as a standard image, taking the coordinate of the reference point in the standard image as a standard coordinate, and calculating the standard coordinate of the reference point on other images except the standard image in acamera visual angle coordinate system according to the moving square and the moving distance of the sickbed; finally, solving a correction coefficient matrix capable of mapping the reference point coordinates of each image to the corresponding standard coordinates; and correcting the to-be-corrected image newly acquired by the camera through the correction coefficient matrix. The CT sickbed can bedirectly used for quickly and accurately correcting the camera.

Description

technical field [0001] The invention relates to the technical field of medical imaging, in particular to a camera calibration method in a CT system. Background technique [0002] In the process of applying machine vision, in order to determine the relationship between the three-dimensional geometric position of a point on the surface of a space object and its corresponding point in the image, it is necessary to establish a geometric model of camera imaging, and these geometric model parameters are camera parameters. These parameters must be obtained through experiments and calculations under most conditions. Whether it is in image measurement or machine vision applications, the calibration of camera parameters is a very critical link. The accuracy of the calibration results and the stability of the algorithm directly affect the accuracy of the camera work results. [0003] The checkerboard calibration method is currently the most commonly used camera calibration method. The...

AI Technical Summary

Problems solved by technology

[0009] 1. Higher requirements on the size and flatness of the checkerboard;

[0010] 2. Checkerboard calibration requires a flat checkerboard calibration board. The price of professional calibration boards is high, and the size of customized calibration boards is relatively large. The portability is poor when installing products in hospitals, and it is not suitable for integration in products.

[0011] 3. The image after checkerboard correction still needs bed calibration to calculate the corresponding relationship between the bed size and pixels, and the calculation is relatively cumbersome

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