×

Processing waveform-based NDE

  • US 7,933,027 B1
  • Filed: 12/02/2008
  • Issued: 04/26/2011
  • Est. Priority Date: 06/27/2008
  • Status: Expired due to Fees
First Claim
Patent Images

1. A process for non-destructive evaluation of a sample using a computer, a display and a computer program implementing an algorithm, said algorithm includes determining the velocity of terahertz electromagnetic radiation in said sample without prior knowledge of the thickness of said sample and determining said thickness of said sample without prior knowledge of said velocity of said terahertz electromagnetic radiation in said sample, said terahertz electromagnetic radiation produced by a source, namely, a transceiver, spaced apart from said sample under test and propagated at the speed of light, c, in a medium located between said source, namely, a transceiver, and said sample, comprising the steps of:

  • emitting and scanning terahertz electromagnetic radiation from said source, namely, said transceiver, said terahertz radiation applied to a plurality of scan points arranged according to x and y coordinates of said sample, said plurality of scan points includes an area at least as large as said surface of said sample;

    recording and storing in a substrate echo waveform data set file, on a scan point by scan point basis, said substrate echo (M″

    ) waveform of said terahertz electromagnetic radiation received from said substrate without said sample present;

    placing said sample on said substrate;

    recording and storing in a back surface echo waveform data set file, on a scan point by scan point basis, the back surface echo (BS) waveform of said terahertz electromagnetic radiation received from said substrate with said sample present;

    recording and storing in a front surface echo waveform data set file, on a scan point by scan point basis, the front surface echo (FS) waveform of said terahertz electromagnetic radiation received from said front surface (FS) of the sample;

    recalling said stored substrate echo (M″

    ) waveform data set file, recalling said stored back surface echo (BS) waveform data set file, and recalling said stored front surface echo (FS) waveform data set file;

    opening and viewing, interactively and selectively, said substrate echo (M″

    ) waveform, said front surface echo (FS) waveform, and said back surface echo (BS) waveform, for a single scan point, said substrate echo (M″

    ) waveform, said front surface echo (FS) waveform, and said back surface echo (BS) waveform being superimposed in a display indicating amplitude and time base of said waveform;

    viewing, interactively and selectively, an algorithm generated display of all scan points and associated substrate (M″

    ) waveforms, associated front surface (FS) waveforms and associated back surface echo (BS) waveforms, for selected scan points of said sample arranged according to x and y scan coordinates;

    gating, interactively, said front surface echo (FS) waveform and said substrate echo (M″

    ) waveform based on ranges determined from viewing selected scan points of said sample, said gating filters said scan points having waveforms beyond the time width of said gates;

    conditioning, said front surface echo (FS) waveform;

    fusing said stored substrate echo (M″

    ) waveform data set file and said stored front surface echo (FS) waveform data set file into said stored back surface echo (BS) waveform data set file and producing a fused data file for each of said scan points;

    viewing and displaying said fused substrate (M″

    ) waveforms, front surface (FS) waveforms and associated back surface echo (BS) waveforms, interactively and selectively, for selected x and y scan coordinates, according to an algorithm generated display of all scan points;

    selecting one of said fused data files, and interactively gating said front surface (FS) echo waveform and interactively gating said back surface (BS) echo waveform of one said selected fused waveform file based on ranges determined from viewing said previously fused waveforms;

    calculating the difference in time, 2τ

    , between said front surface (FS) echo waveforms and said back surface (BS) echo waveforms on a scan point by scan point basis generating and storing a 2τ

    file;

    interactively gating said back surface (BS) echo waveform and interactively gating said substrate (M″

    ) echo waveform of said selected fused waveform file based on ranges determined from viewing said selected fused waveforms;

    calculating according to said algorithm the difference in time, Δ

    t, between said front surface (BS) echo waveforms and said substrate (M″

    ) echo waveforms on a scan point by scan point basis generating and storing a Δ

    t file;

    determining according to said algorithm and storing, on a scan point by scan point basis, the velocity of terahertz electromagnetic radiation in said sample without prior knowledge of the thickness of said sample; and

    ,determining according to said algorithm and storing, on a scan point by scan point basis, said thickness of said sample without prior knowledge of said velocity of said terahertz electromagnetic radiation in said sample.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×