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3D QUANTITATIVE-IMAGING ULTRASONIC METHOD FOR BONE INSPECTIONS AND DEVICE FOR ITS IMPLEMENTATION

  • US 20100185089A1
  • Filed: 04/07/2009
  • Published: 07/22/2010
  • Est. Priority Date: 10/24/2006
  • Status: Abandoned Application
First Claim
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1. A method of 3D Quantitative-Imaging Ultrasonic Tomography for inspecting a heterogeneous object;

  • wherein said method comprises the step of;

    a. providing a 3D quantitative imaging ultrasound tomography system, said system comprises at least;

    i. a three dimensional ultrasonic unit characterized by;

    (a) a grid array of evenly spaced ultrasonic transducers capable of transmitting an ultrasonic wave at an angle to said grid in response to excitation pulses, and capable of producing a signals in response to received ultrasonic waves at an angle to said grid;

    said transducer grid is in acoustic contact with said inspected object; and

    ,(b) a layered system comprising the inspected object, said layered system is characterized by acoustic impedance gradient causing the ultrasonic waves to propagate through said system and the object along a non-linear paths;

    ii. a signal generator generating short excitation pulses;

    iii. a scanning position controller adapted for consecutively emitting said generated excitation pulses and directing said pulses to a selected transmitting transducer in said transducer'"'"'s grid array and receiving signals created in other receiving transducers of grid'"'"'s array in response to said ultrasonic waves emitted by said transmitted transducer and propagating along the non-linearly paths passed through said inspected system according to a predetermined protocol;

    iv. a measuring time unit receiving said signals from said receiving transducers and measuring a time of wave travel between corresponding pair of transmitting transducer and receiving transducer;

    v. a processor adapted for acquiring a plurality of measured travel times corresponding to a plurality of paths between said transmitting and receiving transducers;

    calculating according to the differential approach plurality of time values corresponding to plurality elementary volumes composing of said object and calculating length of elastic wave paths in elementary cells and calculating of said longitudinal wave velocity and porosity corresponding to a plurality of travel times further corresponding to each combination of a pair of adjacent transmitting transducers and a pair of adjacent receiving transducers for direct and reciprocal directions; and

    evaluating longitudinal wave velocity in material matrix part of said heterogeneous object;

    vi. an image formation unit;

    vii. memory(b) providing non-linear ultrasonic waves propagation through the layered system by;

    i. establishing acoustical contact between said grid of transducers and a surface of said layered system in a unilateral way; and

    ii. consecutively transmitting ultrasonic waves by each transducer and receiving ultrasonic waves by the rest of transducers of said grid'"'"'s array said ultrasonic waves being transmitted and received at an angle to the layered system;

    (c) measuring travel times of said ultrasonic waves transmitted and received at said step of consecutively transmitting ultrasonic waves;

    (d) interpreting said layered system containing inspected object as a plurality of elementary cells arranged in columns and rows;

    (e) by means of differential approach calculating travel times corresponding to each elementary cell;

    i. calculating changes in travel times Δ

    tm corresponding to each subsequent cell relatively to the previous cell along each column by combining the average values τ

    m, τ

    m−

    1
    , τ

    dir, τ

    rec from eight travel times of the direct and reciprocal directions according to equation;

    Δ

    τ

    m

    m

    m−

    1


    τ

    dir

    τ

    rec, where τ

    m is the average value between longitudinal wave travel time for direct and reciprocal directions for the transducers arrangement from points m to point (−

    )m, were m is a number of a transducer location;

    τ

    m−

    1
    is an average value between longitudinal wave travel time for direct and reciprocal directions for transducers arrangement from point (m−

    1) to point (−

    m+1);

    τ

    dir is an average value between longitudinal wave travel time for direct and reciprocal directions for transducers arrangement from point (−

    m) to point (m−

    1) and τ

    rec is an average value between longitudinal wave travel time for direct and reciprocal directions for transducers arrangement from point m to point (−

    m+1);

    ii. calculating a sequence of travel time values corresponding to each of said elementary cell of said column by summing said values of said changes travel times in said elementary cells Δ

    τ

    m

    τ

    1, Δ

    τ

    2, Δ

    τ

    3, Δ

    τ

    4 . . . Δ

    τ

    m) and the travel times in said previous elementary cell in said column tm (t1, t2, t3, . . . tm) according to equation;

    τ

    2=t1

    τ

    1, τ

    3=t2

    τ

    2, τ

    3=t2

    τ

    2 . . . and τ

    m=tm−

    1


    τ

    m−

    1
    ;

    (f) calculating of longitudinal wave velocity values associated with ultrasonic waves propagating in each elementary cell, said calculating is carried out by dividing a length of a beam travel in the elementary cell by said travel time calculated at the step (e).ii;

    wherein said travel length associated with a first cells of a columns is equal to 2b/sin α and

    said travel length associated with the rest of cells of the same columns is equal to π

    b, where b is a distance between adjacent transducers and α

    is the incident angle on the layered system surface;

    (g) statistical evaluating of longitudinal wave velocity value associated with ultrasonic waves propagating in the material matrix portion of said inspected object, said evaluating is carried out by means of histogramming of obtained longitudinal wave velocity values corresponding to said plurality of elementary cells;

    (h) calculating of porosity values n for said plurality of elementary cells according to the formula;

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