Patent ID: 6449566
Filing Date: 2002-09-10
Classification: G01N

Abstract:
A method for determining multiple feature variances in a medium, comprising the steps of:selecting a scattering direction relative to a region of interest in a medium; positioning acoustic sources on one side of said scattering direction; positioning acoustic receivers on an opposite side of said scattering direction wherein, for each of said acoustic sources, there is a corresponding one of said acoustic receivers located at a mirror-imaged position relative to said scattering direction such that Bragg scattering wave vector associated with each of said acoustic sources and its corresponding one of said acoustic receivers is parallel to said scattering direction; operating each of said acoustic sources at a unique time to direct a broadband ultrasonic pulse at said region of interest in a first direction herein an acoustic scattered wave reflects from said region of interest in a second direction; detecting each said acoustic scattered wave as a waveform at said corresponding one of said acoustic receivers; digitizing each said waveform to form a digital waveform; converting each said digital waveform to the frequency domain to form a spectral waveform; determining a band of Bragg wave numbers for each said spectral waveform; and determining variations in multiple features of said medium as a function of each said band of Bragg wave numbers.