Performance evaluation of the digital smoothing polynomial filter in ultrasonic IRIS applications

The digital smoothing polynomial filter or Savitzky-Golay filter, which is assumed to be appropriate for ultrasonic IRIS applications due to its ability of conciliation between the high smoothing level and degree of peak retention, fits a set of data points to a polynomial by applying least-squares fitting. In this study, the performance of the digital smoothing polynomial filter is evaluated in terms of signal-to-noise ratio and interface echoes preservation. Moreover, a smoothing polynomial filter that works in a cascade setup is proposed to take advantage of the conciliation ability of the standard filter. The theory and experiments of the polynomial smoothing filter are presented, and graphical results are given. The evaluation results of the digital smoothing polynomial filter showed its efficiency in smoothing and echo signals reproduction. The proposed cascade filter gave considerable advantages.