Investigation of an ultrasonic array imaging method of phase weighting vector total focusing

The conventional vector total focusing method only uses the signal amplitude information, resulting in the imaging quality very affected by the noise, grating lobes, side lobes and so on. In this paper, the signal amplitude and phase information are used together, and then puts forward two kinds of phase weighting vector total focusing method. First, It is based on an analysis of the phase information at the full matrix data, two phase feature parameters, namely the phase coherence factor (PCF) and the sign coherence factor (SCF) are proposed; Then, the whole array is divided into a number of sub-arrays, using the two phase feature parameters to weight the imaging amplitude and consequently to get the weighted amplitude feature vector; finally, compounding the weighted amplitude feature vector of all sub-arrays, the new method for characterizing reflectors is presented, that is phase weighting vector total focusing method. In the simulation and experiment, above three kinds of vector total focusing methods was applied to defects detection. It turned out that the three methods can all achieve direction recognition and length quantitative measurement of defects, but the phase weighting method results is obviously superior to the conventional method results, the methods obtain improvements in SNR and resolution, and the direction and length measurement of defects are more accurate. The research work for the defect non-destructive evaluation provides a feasible method.