Research on phased array ultrasonic total focusing method and its calibration

Total focusing method is an imaging approach using full matrix data which has become a research hotspot due to its advantages such as high accuracy, flexibility and so on. To solve the calibration problem in inspection with wedge coupled, full matrix data and its capture are described, a dual-medium energy attenuation model is established, three parts of calibration coefficient are given by analytical expressions which are directivity, transmission and diffusion attenuation, and a calibration based total focusing method is designed. Three images of the phased array test block type-B are formed using total focusing method. Experimental results show that it is good for the remote reflector with the calibration of root-square-distance, using the attenuation calibration model the attenuation caused by long path length and large deflection angle is better corrected and the energy of the image is more uniform. This calibration based total focusing method has the ability to detect the defects at large deflection angle. The research result shows that missing rate and sizing error can be reduced by calibration based total focusing method effectively.