Line structure light vision sensor calibration method based on parallel bicylindrical target

Abstract

The invention discloses a line structure light vision sensor calibration method based on a parallel bicylindrical target. The method comprises the following steps: placing a target at a proper position at least once by use of the parallel bicylindrical target which moves freely, and a line structure light vision sensor shooting a laser light stripe image on the target; extracting the center point of the light stripe image, and fitting an elliptical image of a light stripe in the image; based on perspective projection transformation, establishing a corresponding equation between two space ellipses and their images; solving a light plane equation by taking equivalence between the short axes of the ellipses and the diameter of a cylinder as a constraint condition; and obtaining an optimal solution of the light plane equation through a nonlinear optimization method. The method provided by the invention is suitable for calibration of a line structure vision sensor in an onsite complex light environment and even under the condition that a camera is provided with an optical filter, and is especially suitable for onsite rapid high-precision calibration of multiple line structure light vision sensors in a narrow space or at difference angles.

Description

technical field [0001] The invention relates to a sensor calibration technology, in particular to a calibration method of a line structured light vision sensor based on parallel double cylinder targets. Background technique [0002] Structured light 3D vision measurement has been widely used in industrial environments in recent years due to its characteristics of large range, non-contact, fast and high precision. The line structured light method and the grating structured light method use lasers and cameras to build a three-dimensional vision sensor, which is suitable for three-dimensional shape measurement of objects in complex environments. [0003] The calibration process of line structured light vision sensor includes two aspects: camera internal parameter calibration and light plane parameter calibration. There are many literatures on camera internal parameter calibration, so we focus on the light plane parameter calibration process. There are many methods for calibra...

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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