Magneto-optic image enhancement method based on optical flow algorithm

Abstract

The invention discloses a magneto-optic image enhancement method based on an optical flow algorithm. Low-frequency AC excitation is used for excitation of a magnet yoke, an image set is obtained under different signal intensities through a periodic variable magnetic field, and a low-frequency signal enables magnetic force lines to pass through a deeper region of a detected object, thereby enabling a magneto-optic image to reflect the defect information of the deeper region, and reducing the impact from the skin effect. Meanwhile, the multi-point sampling and photographing (collection) can be carried out in one period, thereby increasing the data information of the magneto-optic image. However, the magneto-optic image obtained through the above method has the interference noise caused by magnetic domain movement under the action of a low-frequency AC signal, and is liable to be mixed with the defect information, thereby reducing the image detection information. Therefore, the method employs a pyramid optical flow algorithm for the iteration processing of the magneto-optic image, achieves the accumulation of feature points generating optical flow motion, and obtains an optical flow enhanced image. The enhanced image is more apparent in image gradient changes, greatly reduces the interference, and is more visual in defect information.

Description

technical field [0001] The invention belongs to the technical field of nondestructive testing of magnetic materials, and more specifically relates to a magneto-optical image enhancement method based on an optical flow algorithm. Background technique [0002] Non-destructive testing (Non-destructive testing) refers to the use of physical quantity changes caused by abnormal internal structures of materials such as heat, sound, light, electricity, and magnetism on the premise of not damaging or affecting the internal organization of the object to be tested. The change of the physical quantity caused by the change of the material structure is detected, and the change value of the physical quantity is measured to invert the change of the material structure. It is worth noting that the change value of the physical quantity obtained in the experiment may contain a lot of other information, so it is necessary to exclude other external disturbances to make a reliable judgment on the ...

AI Technical Summary

Problems solved by technology

However, due to the DC excitation, not only the magnetizer has a large volume and high energy consumption, but also under a constant magnetization field, the leakage field is constant, and the amount of information obtained is limited, which is not conducive to the extraction of defect features, and the anti-interference ability is weak;

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