Patent ID: 7978341
Filing Date: 2011-07-12
Classification: G01B,G01N

Abstract:
1. A multi-channel laser interferometric method for measuring the displacement of a surface of a material subjected to ultrasound, which comprises: generating a laser beam having a predetermined intensity; dividing the laser beam into a reference beam and a probe beam having respective intensities representing minor and major fractions of the predetermined intensity; passing the probe beam through an optical lens to focalize the probe beam onto the surface of the material subjected to ultrasound, thereby scattering same; expanding the reference beam; combining the scattered probe beam collected by said optical lens with said expanded reference beam to obtain an optical fringe signal; receiving said optical fringe signal on at least one array of photodetectors, wherein said optical fringe signal fully covers said array and each photodetector of the array defines a channel, having a given aperture smaller than the aperture of said optical lens to receive a portion of said optical fringe signal and converting said portion of said optical fringe signal into an electrical signal; processing for each channel said electrical signals through circuitry means; summing electrically said processed signals to extract an output signal correlated to the motion of said surface.