Parameter estimation and the importance of phase in acoustic microscopy

The proper operation of the scanning laser acoustic microscope depends on the determination of many parameters, such as the depth of subsurface structures and the velocity and wavelength of sound in the specimen. Two methods of determining these parameters are presented which use the contrast and the variance of the subsurface images formed from the detected wavefields to provide a quantitative measure of parameter accuracy. This microscope is capable of detecting both the magnitude and phase of the received wavefield. The importance of the phase information in image reconstruction and specimen evaluation is described