Line structured light visual sensor calibration method based on sawtooth target

Abstract

The present invention discloses a line structured light visual sensor calibration method based on a sawtooth target. The method comprises: in the condition that a camera has no an optical filter, performing calibration of the camera in a line structured light visual sensor; installing an optical filter at the front portion of the camera lens, allowing the camera to shoot a sawtooth target image with a light bar, obtaining image coordinates of the intersection point of the light bar and the target tooth-shaped edge, namely the image coordinates of feature points, and solving the three-dimensional coordinates of the feature points in the camera coordinate system based on the principle of cross-ratio invariance; considering an optical filter refraction model, and solving the parameters of the optical fiber and the three-dimensional coordinates of the feature points after optimization in the camera coordinate system through the nonlinear optimization method; and moving the target for more than two times, obtaining the three-dimensional coordinates of all the position feature points of the target in the camera coordinate system, fitting the three-dimensional coordinate points to solve a light plane equation, and completing the calibration. The line structured light visual sensor calibration method based on the sawtooth target is suitable for a field complex light environment and even can complete line structured vision sensor calibration in the condition that the camera has the optical filter.

Description

technical field [0001] The invention relates to the technical field of sensor calibration, in particular to a calibration method for line structured light vision sensors based on sawtooth targets. Background technique [0002] Structured light 3D vision measurement can achieve large-scale, non-contact, fast and high-precision measurement in industrial environments, so it is widely used. The line structured light method and the grating structured light method are visual sensors composed of lasers and cameras, which can be used to measure the three-dimensional shape of objects in complex environments. [0003] The calibration process of line structured light vision sensor includes camera internal parameter calibration and light plane parameter calibration. Among them, there are many studies on camera internal parameter calibration, so we focus on the light plane parameter calibration process. There are many methods for calibrating the light plane parameters. For example, De...

AI Technical Summary

Problems solved by technology

[0004] However, the existing main line structured light vision sensor calibration methods need to combine the feature points on the target and the light strip image information to calculate the light plane equation

Due to the relatively strong power of the laser, it is difficult to capture the image information of the feature points and light stripes on the target clearly at the same time, especially in complex light environments such as uneven light intensity on the spot, it is even more difficult to obtain clear images at the same time

Especially when the camera is equipped with a filter, it is even impossible to capture the feature point image of the target

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