Research On Imaging Methods For Ultrasonic Phased Array Based On Array A-scan Signals

The inspection imaging technology of Ultrasonic Phased Array make beam-formingwhich is send and received by array transducer controlled flexible through control the phaseof each element accurately, so as to detect the mechanical structure and components withall-round, multi-angle beam scanning, the imaging results show the internal traits intuitively.However, the research on Ultrasonic Phased Array in our country has a big disparity withother countries. At present, the equipment of Ultrasonic Phased in our industrial detection isimported from abroad, the high price restrict its application in the field of industrialnon-destruction in our country.In this dissertation, we design an Ultrasonic Phased Array imaging scheme which basedon array A-scan signals. This difference in this scheme and the Ultrasonic Phase Arrayequipment is that, this scheme imitates delay receiving through array A-scan signals postprocessed. To achieve the effect of beam-forming deflection, then combine the differentdeflection angle signals to S-scan imaging and to achieve the effect of phased array defective..After the research of the scheme, we hope to improve the situation that the use of UltrasonicPhased Array depends on importing from abroad in our country and reduce the cost of theequipment.The scheme acquires N*N A-scan signals via a ultrasonic array transducer which has Nelements, and then calculate the difference of phase of each A-scan signals according to thedeflection angle of beam-forming, then translate each A-scan signals to imitate the delay ofsignal received, so that get the effect of deflection. In the end, combine the different deflectionbeam-forming to S-scan imaging. Aimed at the low delay precision because of low sampling frequency, the colorcontinuity in defection is poor after coordinate transformation, this dissertation first to A-scansignal interpolation processing, improve the sampling frequency, so as to solve the problem oflow precision of time delay, then put forward to a new method of imageprocessing Research on Imaging Methods for Ultrasonic Phased Array Based on ArrayA-scan Signals, after the process of B-scan imaging, the question of defection of poorcontinuity is solved, laid the foundation for the follow-up of quantitative analysis of thedefection.At last, the dissertation designs the experiment to verify the Ultrasonic Phased Arrayimaging scheme, and design a comparative experiment with the help of ultrasonic phasedarray equipment of the laboratory, by comparing the results, verify the imaging methods forultrasonic phased array based on array A-scan signals is proposed in this paper.