A method and system for detecting micro-defects on the surface and subsurface of bronze wares

Abstract

The invention relates to a method and a system for detecting microdefects on the surface and the sub surface of bronze ware. The detection method comprises the following steps: a PLC controls two laser devices to emit two beams of laser with different center frequencies, and the two beams of laser work on the same point on the surface of the defect-containing bronze ware to be detected through a light path system set; a capacitive type displacement sensor for measuring a laser excitation ultrasonic signal is placed on the surface of the same side, which receives laser radiation, of the bronze ware to be detected; the received ultrasonic signal is stored in a data processing system for frequency analysis use by a data acquisition system set; the data processing system set can carry out two-dimensional planar imaging detection on a defect on the surface or the sub surface of the bronze ware; and the defect depth can be detected. The method and the system which are disclosed by the invention can scan and detect the three-dimensional position and size information of the defect on the surface or sub surface of the bronze ware, and have the advantages of high efficiency, high precision, no damage to a detected body and the like.

Description

technical field [0001] The invention belongs to the field of archaeology, and in particular relates to a method for detecting micro-defects on the surface and sub-surface of bronze ware; the invention also relates to a system for implementing the method for detecting micro-defects on the surface and sub-surface of bronze ware. Background technique [0002] my country is an ancient civilization with a long history. With the development of Chinese archaeology, a large number of bronze artifacts have been unearthed. Bronze wares mainly refer to: bronze wares made by ancient traditional crafts, with tin, lead and copper as basic elements. Due to the age, especially those bronze cultural relics that were buried underground and unearthed, it is common to have defects, fractures or defects on the surface and subsurface. And for the restoration of the defective parts of bronze wares, traditional restoration methods often use methods such as filling, caulking and patching. These me...

AI Technical Summary

Problems solved by technology

However, the defect detection of the device described in this patent has the following problems: (1) It can only predict the existence of defects qualitatively, and cannot give the three-dimensional size information of the defects; (2) The abnormal scattering signal received by the air-coupled probe is not necessarily caused by the bronze surface and sub-surface defects, the abnormality of the properties of the bronze surface and sub-surface itself, such as anisotropy of property distribution, will also cause abnormal ultrasonic signals and lead to system misjudgment

However, the following problems still exist in the application of these patents: (1) Ultrasonic waves are excited on the surface of the bronze ware and sub-surface / test block, but longitudinal waves are used at the center of the bronze ware surface and sub-surface / test block (corresponding points on the lower surface) / body wave probe receives ultrasound

In fact, it is not easy to install an ultrasonic probe at the center of the lower surface of the bronze ware, because it will be limited by the space size of the bronze ware; and as mentioned before, the longitudinal wave / body wave probe will corrode the bronze ware because it needs to use a couplant , which directly limits the use occasions of these patented devices

(2) These patented devices only use the longitudinal wave / bulk wave signal excited by the laser in the defect detection

This is also the reason why CN 103808802A needs to add a "transparent covering layer" on the radiated surface of the tested material to increase the energy of the body wave. The reason why it needs to be in direct contact with the surface and sub-surface of the bronze ware cannot be used directly under special environmental conditions (such as an oxygen-free state, etc.)

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