Underwater measuring method based on vision

Abstract

The invention provides an underwater measuring method based on vision.The underwater measuring method comprises the steps that firstly, pre-calibration in air is carried out, wherein two cameras are fixed in sealed equipment and shoot multiple plane calibration images, internal parameter matrixes of the two cameras are calibrated respectively, and a basic matrix between the two cameras is calibrated by shooting two images of a plane calibration plate; secondly, underwater cameras are calibrated, wherein underwater three-dimensional calibration plate images are shot, and external parameter matrixes of all the cameras and parameters of distances between the centers of the cameras and a refraction plane are calibrated.The invention discloses an underwater dimension measuring method for achieving precise calibration of the cameras through an established accurate underwater imaging model.Underwater two-dimension measurement and binocular three-dimension measurement are achieved through camera calibration parameters, and it is verified through experiments that the precision of underwater two-dimension measurement and binocular three-dimension measurement ranges from -0.2 mm to +0.2 mm in the method.The technology can be widely applied to underwater accurate measurement and precise detection.

Description

technical field [0001] The invention relates to the field of underwater measurement, in particular to a vision-based underwater measurement method. Background technique [0002] With the gradual depletion of terrestrial oil and gas resources, ocean development, which accounts for 71% of the earth's area, has become one of the most important energy strategies of all countries in the world. At present, more than 100 countries and regions in the world are engaged in offshore oil and gas exploration and development, and invest tens of billions of dollars in research and development every year. In marine and deep-sea operating environments, submarine pipelines, mooring systems, and offshore oil drilling equipment are prone to damage due to seawater corrosion, self-abrasion, quicksand wave impact, and oil and gas loads. It is extremely difficult to detect and maintain equipment, and once an accident occurs, the loss is extremely serious. The technology disclosed in the invention...

AI Technical Summary

Problems solved by technology

[0004] The underwater three-dimensional measurement technology based on active vision in the above prior art has the following deficiencies: 1) there is a detection blind spot in the laser triangulation measurement; 2) the system is large in size and weight, and lacks flexibility; 3) the laser needs to be scanned during the scanning process. The measurement of one surface can only be completed by moving according to the predetermined trajectory, and the operation is difficult; 4) The water medium and impurities cause serious scattering to the collimated laser beam, which makes the ideal beam form a divergent spot after imaging, which seriously affects the measurement accuracy of the system

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