Patent ID: 6854331

Claim:
A method for measuring material characteristics comprising: an incident wave frequency component analysis step of performing a frequency component analysis of a pulse wave introduced into a material to be measured and obtaining frequencies of respective sine wave components and a spectral distribution of phase differences obtained from sine wave components and cosine wave components at those frequencies; a reflected wave frequency component analysis step of performing a frequency component analysis of a wave reflected from the material to which was introduced the incident wave and obtaining frequencies of respective sine wave components and a spectral distribution of phase differences obtained from sine wave components and cosine wave components at those frequencies; and a frequency/phase difference specification step of comparing the spectral distribution of the incident wave with the spectral distribution of the reflected wave and specifying a phase difference θx, which is a difference between the phase of the incident wave and the phase of the reflected wave at each frequency fx, and determining about a maximum change in the phase difference, wherein a characteristic value of the material corresponding to the hardness of the material is obtained from values of fx and θx.