Ultrasound characterization of 3-dimensional flaws

Claim 1

A method which uses an improved Born approximation technique to determine with ultrasound a 3-dimensional flaw shape of flaws of general shape comprising the steps of : (a) taking pulse echo measurements and acquiring return echo waveforms using broadband pulses of ultrasound that are incident on a flaw in an object at a plurality of angles between 0 and π in a chosen plane; (b) Fourier transforming said echo waveforms to yield lines of Fourier components of a characteristic function which is defined as equal to 1 inside the flaw and 0 outside the flaw; (c) dividing each line of Fourier components by a quantity proportional to incident ultrasound angular frequency squared to yield lines of spatial Fourier components of the flaw shape; (d) performing a 1-dimensional inverse Fourier transform on every such line of spatial Fourier components to yield a plurality of 1-dimensional projections; (e) performing a 2-dimensional reconstruction to reconstruct a 2-dimensional project image from said 1-dimensional projections; (f) rotating the plane on which said pulse echo measurements are made and repeating steps (a) to (e) to produce a plurality of said 2-dimensional projection images; and (g) reconstructing the 3-dimensional flaw shape from said 2-dimensional projection images through a 3-dimensional tomographic reconstruction process.

Claim 2

A method which uses an improved Born approximation technique to determine with ultrasound a 3-dimensional flaw shape of flaws of general shape comprising the steps of : (a) taking pulse echo measurements and acquiring return echo waveforms using broadband pulses of ultrasound that are incident on a flaw in an object at a plurality of angles between 0 and π in a chosen plane; (b) Fourier transforming said echo waveforms to yield lines of Fourier components of a characteristic function which is defined as equal to 1 inside the flaw and 0 outside the flaw; (c) dividing each line of Fourier components by a quantity proportional to incident ultrasound angular frequency squared to yield lines of spatial Fourier components of the flaw shape; (d) performing a 1-dimensional inverse Fourier transform on every such line of spatial Fourier components to yield a plurality of 1-dimensional projections; (e) performing a 2-dimensional reconstruction to reconstruct a 2-dimensional project image from said 1-dimensional projections; (f) rotating the plane on which said pulse echo measurements are made and repeating steps (a) to (e) to produce a plurality of said 2-dimensional projection images; and (g) reconstructing the 3-dimensional flaw shape from said 2-dimensional projection images through a 3-dimensional tomographic reconstruction process.

Claim 4

The method which uses an improved Born approximation technique to determine with ultrasound a 3-dimensional flaw shape of flaws of general shape comprising the steps of: (a) taking pulse echo measurements and acquiring return echo waveforms using broadband pulses of ultrasound that are incident on a flaw in an object at a plurality of angles between 0 and π in a chosen plane; (b) Fourier transforming said echo waveforms to yield lines of Fourier components of a characteristic function which is defined as equal to 1 inside the flaw and 0 outside the flaw; (c) dividing each line of Fourier components by a quantity proportional to incident ultrasound angular frequency squared to yield lines of spatial Fourier components of the flaw shape; (d) angularly orienting said lines of spatial Fourier components to result in a plane of Fourier components; (e) performing a 2-dimensional inverse Fourier transformation to yield a 2-dimensional projection image of the flaw shape; (f) rotating the plane on which said pulse echo measurements are made and repeating steps (a) to (e) to produce a plurality of said 2-dimensional projection images; and (g) reconstructing the 3-dimensional flaw shape from said 2-dimensional projection images through a 3-dimensional tomographic reconstruction process.

Claim 5

The method which uses an improved Born approximation technique to determine with ultrasound a 3-dimensional flaw shape of flaws of general shape comprising the steps of: (a) taking pulse echo measurements and acquiring return echo waveforms using broadband pulses of ultrasound that are incident on a flaw in an object at a plurality of angles between 0 and π in a chosen plane; (b) Fourier transforming said echo waveforms to yield lines of Fourier components of a characteristic function which is defined as equal to 1 inside the flaw and 0 outside the flaw; (c) dividing each line of Fourier components by a quantity proportional to incident ultrasound angular frequency squared to yield lines of spatial Fourier components of the flaw shape; (d) angularly orienting said lines of spatial Fourier components to result in a plane of Fourier components; (e) performing a 2-dimensional inverse Fourier transformation to yield a 2-dimensional projection image of the flaw shape; (f) rotating the plane on which said pulse echo measurements are made and repeating steps (a) to (e) to produce a plurality of said 2-dimensional projection images; and (g) reconstructing the 3-dimensional flaw shape from said 2-dimensional projection images through a 3-dimensional tomographic reconstruction process.