Secondary calibration method for three-dimensional vision measurement system

Abstract

The invention relates to the technical field of vision measurement system calibration, and discloses a secondary calibration method for a three-dimensional vision measurement system, which comprises the following steps: S1, carrying out primary calibration on the system according to world coordinate values and image coordinate values; s2, performing three-dimensional reconstruction on the standard component by using a system calibrated for the first time, and evaluating a calibration error according to a reconstruction result; s3, according to the calibration error evaluation result, the world coordinate value is adopted for optimization when the system is calibrated for the first time, and the optimized world coordinate value is used for secondary calibration of the system calibrated for the first time; and S4, reconstructing the standard component by using the system after secondary calibration until an error between a result of reconstructing the standard component and a theoretical value of the standard component meets a preset condition, and obtaining a high-precision calibration result. Based on an optimization algorithm, deviation analysis is carried out on a reconstruction result of a standard component and a theoretical value of the standard component, and high-precision secondary calibration is carried out on the system by taking the minimum error of the reconstructed standard component as an optimization target.

Description

technical field [0001] The invention relates to the technical field of visual measurement system calibration, in particular to a secondary calibration method for a three-dimensional visual measurement system. Background technique [0002] Vision measurement has the advantages of non-contact, fast measurement speed, high precision, flexible measurement method, etc., and is widely used in defect detection, three-dimensional surface measurement and other fields. The 3D visual measurement method has become one of the best methods for 3D measurement because of its fast speed, high precision, and strong practicability. The key to 3D visual measurement is to obtain the pixel coordinates of the picture taken by the camera and its corresponding coordinates in the world coordinate system. In order to accurately describe the relationship, it is necessary to calibrate the parameters of the measurement system composed of cameras, that is, system calibration. In 3D vision measurement, sy...

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Problems solved by technology

[0003] The calibration of the 3D visual measurement system first needs to obtain the coordinates of the world coordinate system and the coordinates of the image coordinate system. The world coordinates of the world coordinate system are obtained by establishing the world coordinate system. The coordinate system established at this time is called the ideal coordinate system. Calibration target pose error, there will be a certain deviation between the actual world coordinate system and the ideal coordinate system, so there is also a deviation between the actual value and the ideal value in the world coordinate system obtained, this deviation will affect the accuracy of system calibration

On the other hand, after the calibration of the 3D vision measurement system, when the system is placed for a long time or bumps occur during the handling of the system, the internal structure of the system will drift slightly. With the change of the internal structure of the system, the parameters of the measurement system will also change. changed, the results of the initial system calibration will no longer apply

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