Water immersion ultrasonic imaging detection method for inhibiting interface echo interference

Abstract

The invention discloses a water immersion ultrasonic imaging detection method for inhibiting interface echo interference. A pulse echo array signal phase acquired by the water immersion ultrasonic system is extracted, and a characteristic value for representing the phase consistency degree of each pixel point in the ultrasonic image is established through a delay superposition or wave field extrapolation algorithm. According to the phase consistency difference between defect echoes and interface echoes, a threshold screening method or a power transformation method is used for adjusting the phase consistency, the weight proportion of characteristic values is optimized, interference of the interface echoes on defect judgment is effectively restrained by highlighting the defect echo weights with the higher phase concentration degree, and defect misjudgment and missed judgment in automatic detection are reduced. The method provided by the invention belongs to self-adaptive imaging processing, does not need any priori information and extra operation except the water layer and necessary parameters for imaging, is very suitable for being implemented on automatic ultrasonic detection equipment, and has good popularization and application prospects.

Description

technical field [0001] The invention relates to the field of ultrasonic nondestructive testing, in particular to a water immersion ultrasonic imaging testing method for suppressing interface echo interference. Background technique [0002] Compared with the contact ultrasonic imaging detection method, the probe does not directly contact the workpiece during the water immersion ultrasonic imaging detection process, the coupling condition is stable, the detection results have higher repeatability, and it can be applied to the detection of workpieces with rough surfaces and complex shapes , It is more convenient to realize the automatic detection of industrial products, and it plays a pivotal role in the non-destructive testing and evaluation of products in the processing and manufacturing industry. However, due to the difference in sound velocity and density between water and metals, ceramics, resins and other materials, ultrasonic waves are emitted between the acoustic impeda...

AI Technical Summary

Problems solved by technology

However, due to the difference in sound velocity and density between water and materials such as metals, ceramics, and resins, ultrasonic waves are emitted between the acoustic impedance interfaces formed between water and the workpiece, resulting in interface echoes in the detection signal / image

Therefore, the interface echoes in water immersion imaging detection, especially the existence of secondary and higher-order interfaces, will seriously interfere with the detection personnel's identification of product defect echoes, which can easily cause defects to be missed or misjudged, and damage the product. Quality brings serious safety hazards

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