Machine vision-based ship hull six-degree-of-freedom measurement method

Abstract

The invention discloses a machine vision-based ship hull six-degree-of-freedom measurement method. The method includes the following steps that: a RGB three-color marker is posted on a target ship, when the hull of the ship moves, the marker moves with the hull of the ship, two cameras are mounted at different positions, and the angles of the cameras are adjusted, so that the shooting range of the cameras can cover the movement range of the marker, and the cameras carry out image acquisition; images acquired by the cameras are preprocessed, and a RGB color occupancy volume-based segmentation algorithm is adopted to perform image segmentation operation, so that boundary parameters can be obtained, qualified feature points are made to be contained in a boundary range; and a binocular three-dimensional reconstruction method is adopted to obtain the three-dimensional coordinate values of the feature points; and the six degrees of freedom of the hull of the ship are decomposed, and the three-dimensional coordinates of P (x, y, z) at any one time point and the coordinates P'(x', y',z') of a next time point are known, so that a translation vector T(delta x, delta y, delta z) and a rotation vector R (alpha, beta, gamma) which are corresponding to the movement of the hull of the ship are obtained. With the machine vision-based ship hull six-degree-of-freedom measurement method of the invention adopted, real-time and non-contact measurement of six-degree-of-freedom movement of the hull of the ship in regular waves and irregular waves can be realized, and accuracy satisfies engineering requirements.

Description

technical field [0001] The invention belongs to the field of machine vision measurement, in particular to a non-contact real-time measurement method for measuring six degrees of freedom of a hull based on machine vision. Background technique [0002] The traditional contact measurement method is to use a ruler to measure the displacement value, use a gyroscope to measure the shaking angle, record the signal through an optical oscilloscope, and manually read and analyze it. The accuracy is low, a waste of manpower and material resources, and cannot meet the requirements of use. In recent years, with the development of science and technology, some companies have developed and designed a contact six-component test method, which uses displacement and angle sensors to measure the corresponding signals, and then uses the decoupling formula to calculate the six variables. This method has been put into use . However, the contact six-component test method also has shortcomings, beca...

AI Technical Summary

Problems solved by technology

Although there are some foreign products with high measurement accuracy and fast measurement speed, they are expensive and require high equipment maintenance costs, so they are rarely used in China.

In recent years, some domestic studies have basically completed the PC-based non-contact six-component measurement method framework, but due to insufficient precision and slow measurement speed, it has not been practically applied.

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