Acoustic microscopy investigations of nonplanar surfaces

It is well known that the acoustic microscope is used to characterise planar objects via the V(z) signature. Extending this technique to curved surfaces, it is demonstrated theoretically, and on stainless steel balls, that the spacing Delta z is no longer constant as the specimen is defocused and varies with the curvature radii. FFT techniques enable the correcting procedure to be found and hence the redetermination of the exact acoustic properties.