Bore reconstruction of tubular ducts from its acoustic input impedance curve

In order to get accurate bore information of tubular objects from acoustical input impedance measurements an optimization approach is proposed and investigated. The waveguide model used by the optimizer is reviewed and the impedance measurement setup is described. Reconstruction results are presented and discussed. Sensitivity of input impedance magnitude to bore variation indicates that axial accuracy can be improved without increasing the sampling rate. Advantages of the method are its increased numerical stability, its tolerance to white noise on top of measured data, no requirement to measure phase, and the fact that measured data need not to be contiguous in the frequency domain. Frequency bands which are difficult to measure can be omitted.