Industrial fixed-focus camera parameter calibration method based on moving square target calibration object

Abstract

The invention relates to an industrial fixed-focus camera parameter calibration method based on a moving square target calibration object. According to the method, the square target calibration object is used for calibrating camera parameters, four target points are arranged on the square target calibration object, and the geometric centers of the four target points form a square. The method includes the following steps that (1) a camera coordinate system and an imaging plane coordinate system are built according to a pinhole model equivalent light path diagram; (2) a camera is used for collecting images of a target before and after horizontal movement to obtain pixel coordinates of the four target points in an imaging plane in each image, and the horizontal movement distance of the target is recorded; (3) iterative computation is conducted on camera parameters id according to the pixel coordinates and the horizontal movement distance in the step (2); (4) external parameters of the camera are calculated according to the camera parameters id. Compared with the prior art, the industrial fixed-focus camera parameter calibration method has the advantages of being rapid, simple, convenient, high in calibration result accuracy and the like.

Description

technical field [0001] The invention relates to the technical field of camera calibration, in particular to an industrial fixed-focus camera parameter calibration method based on a moving square target calibrator. Background technique [0002] Ordinary industrial digital cameras have many advantages in image acquisition, but because they are non-measurement cameras, their digital images cannot be processed by ordinary digital photogrammetry methods. Ordinary industrial digital cameras can be used for photogrammetry after calibrating the camera parameters. The calibration of the camera is mainly to accurately determine the internal parameters of the camera corresponding to the corresponding imaging model. [0003] The imaging model describes the correspondence between the object point in the space coordinate system and its image point on the image plane. Usually, industrial fixed-focus cameras can use the pinhole model to obtain the three-dimensional coordinates of the object...

AI Technical Summary

Problems solved by technology

[0005] For the first calibration method, although the size of the calibration object is accurate, the external parameters of the camera relative to the calibration object cannot be accurately measured, so the first method needs to collect multiple high-quality calibration images to optimize the solution of internal parameters , the manual operation error of this method is large, the process is cumbersome, and accurate results can only be obtained in the case of repeated calibration

The second method has no external reference object and is very flexible to use, but the image processing technology is not mature, and there are too many unknown parameters, it is difficult to obtain accurate and stable calculation results

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