| Popis: |
A method is provided for determining multiple feature variances in a medium. Acoustic sources are positioned on one side of a selected scattering direction. Acoustic receivers are positioned on an opposite side of the selected scattering direction such that, for each acoustic source, there is a corresponding acoustic receiver located at a mirror-imaged position relative to the selected scattering direction, and such that a Bragg scattering wave vector associated with each acoustic source/receiver pair is parallel to the selected scattering direction. Each acoustic source is operated at a unique time to direct a broadband ultrasonic pulse at the region of interest. An acoustic scattered wave reflects from the region of interest and is detected as a waveform at the pair's acoustic receiver. Each waveform is converted to the frequency domain to form a spectral waveform. A band of Bragg wave numbers is determined for each spectral waveform. Variations in multiple features of the medium are then determined by solving a complex acoustic scatter relationship as a function of the band of Bragg wave numbers associated with the particular source/receiver pair. |
